追記です。

名前：SNMPTrap
タイプ：SNMPトラップ
キー：snmptrap.fallback
アプリケーション：SNMPTrap

にしています。
キーはsnmptrap[]にしても状況は同じです。

これまではアイテムのステータスが有効になっていましたが、
取得不可に変わってしまいました。

続きです。

domain.com
END

# Configures how IP addresses contained in the VALUE of the variable bindings are handled.
# This only applies to the values for $n, $+n, $-n, $vn, $+*, $-*.
# Set to 0 to disable resolving ip address to host names
# Set to 1 to enable resolving ip address to host names
# Note: net_snmp_perl_enable *must* be enabled. The strip_domain settings influence the
# format of the resolved host name. DNS must be enabled (dns_enable)
resolve_value_ip_addresses = 0

# Set to 1 to enable the use of the Perl module from the UCD-SNMP / NET-SNMP package.
# This is required for $v variable substitution to work, and also for some other options
# that are enabled in this .ini file.
# Set to 0 to disable the use of the Perl module from the UCD-SNMP / NET-SNMP package.
# Note: Enabling this with stand-alone mode can cause SNMPTT to run very slowly due to
# the loading of the MIBS at startup.
net_snmp_perl_enable = 1

# This sets the best_guess parameter used by the UCD-SNMP / NET-SNMP Perl module for
# translating symbolic nams to OIDs and vice versa.
# For UCD-SNMP, and Net-SNMP 5.0.8 and previous versions, set this value to 0.
# For Net-SNMP 5.0.9, or any Net-SNMP with patch 722075 applied, set this value to 2.
# A value of 2 is equivalent to -IR on Net-SNMP command line utilities.
# UCD-SNMP and Net-SNMP 5.0.8 and previous may not be able to translate certain formats of
# symbolic names such as RFC1213-MIB::sysDescr. Net-SNMP 5.0.9 or patch 722075 will allow
# all possibilities to be translated. See the FAQ section in the README for more info
net_snmp_perl_best_guess = 2

# Configures how the OID of the received trap is handled when outputting to a log file /
# database. It does NOT apply to the $O variable.
# Set to 0 to use the default of numerical OID
# Set to 1 to translate the trap OID to short text (symbolic form) (eg: linkUp)
# Set to 2 to translate the trap OID to short text with module name (eg: IF-MIB::linkUp)
# Set to 3 to translate the trap OID to long text (eg: iso...snmpTraps.linkUp)
# Set to 4 to translate the trap OID to long text with module name (eg:
# IF-MIB::iso...snmpTraps.linkUp)
# Note: -The output of the long format will vary depending on the version of Net-SNMP you
# are using.
# -net_snmp_perl_enable *must* be enabled
# -If using database logging, ensure the trapoid column is large enough to hold the
# entire line
translate_log_trap_oid = 0

# Configures how OIDs contained in the VALUE of the variable bindings are handled.
# This only applies to the values for $n, $+n, $-n, $vn, $+*, $-*. For substitutions
# that include variable NAMES ($+n etc), only the variable VALUE is affected.
# Set to 0 to disable translating OID values to text (symbolic form)
# Set to 1 to translate OID values to short text (symbolic form) (eg: BuildingAlarm)
# Set to 2 to translate OID values to short text with module name (eg: UPS-MIB::BuildingAlarm)
# Set to 3 to translate OID values to long text (eg: iso...upsAlarm.BuildingAlarm)
# Set to 4 to translate OID values to long text with module name (eg:
# UPS-MIB::iso...upsAlarm.BuildingAlarm)
# For example, if the value contained: 'A UPS Alarm (.1.3.6.1.4.1.534.1.7.12) has cleared.',
# it could be translated to: 'A UPS Alarm (UPS-MIB::BuildingAlarm) has cleared.'
# Note: net_snmp_perl_enable *must* be enabled
translate_value_oids = 1

# Configures how the symbolic enterprise OID will be displayed for $E.
# Set to 1, 2, 3 or 4. See translate_value_oids options 1,2,3 and 4.
# Note: net_snmp_perl_enable *must* be enabled
translate_enterprise_oid_format = 1

# Configures how the symbolic trap OID will be displayed for $O.
# Set to 1, 2, 3 or 4. See translate_value_oids options 1,2,3 and 4.
# Note: net_snmp_perl_enable *must* be enabled
translate_trap_oid_format = 1

# Configures how the symbolic trap OID will be displayed for $v, $-n, $+n, $-* and $+*.
# Set to 1, 2, 3 or 4. See translate_value_oids options 1,2,3 and 4.
# Note: net_snmp_perl_enable *must* be enabled
translate_varname_oid_format = 1

# Set to 0 to disable converting INTEGER values to enumeration tags as defined in the
# MIB files
# Set to 1 to enable converting INTEGER values to enumeration tags as defined in the
# MIB files
# Example: moverDoorState:open instead of moverDoorState:2
# Note: net_snmp_perl_enable *must* be enabled
translate_integers = 1

# Allows you to set the MIBS environment variable used by SNMPTT
# Leave blank or comment out to have the systems enviroment settings used
# To have all MIBS processed, set to ALL
# See the snmp.conf manual page for more info
#mibs_environment = ALL

# Set what is used to separate variables when wildcards are expanded on the FORMAT /
# EXEC line. Defaults to a space. Value MUST be within quotes. Can contain 1 or
# more characters
wildcard_expansion_separator = " "

# Set to 1 to allow unsafe REGEX code to be executed.
# Set to 0 to prevent unsafe REGEX code from being executed (default).
# Enabling unsafe REGEX code will allow variable interopolation and the use of the e
# modifier to allow statements such as substitution with captures such
# as: (one (two) three)(five $1 six)
# which outputs: five two six
# or: (one (two) three)("five ".length($1)." six")e
# which outputs: five 3 six
#
# This is considered unsafe because the contents of the regular expression
# (right) is executed (eval) by Perl which *could contain unsafe code*.
# BE SURE THAT THE SNMPTT CONFIGURATION FILES ARE SECURE!
allow_unsafe_regex = 0

# Set to 1 to have the backslash (escape) removed from quotes passed from
# snmptrapd. For example, " would be changed to just "
# Set to 0 to disable
remove_backslash_from_quotes = 0

# Set to 1 to have NODES files loaded each time a trap is processed.
# Set to 0 to have all NODES files loaded when the snmptt.conf files are loaded.
# If NODES files are used (files that contain lists of NODES), then setting to 1
# will cause the list to be loaded each time an EVENT is processed that uses
# NODES files. This will allow the NODES file to be modified while SNMPTT is
# running but can result in many file reads depending on the number of traps
# received. Defaults to 0
dynamic_nodes = 0

# This option allows you to use the $D substitution variable to include the
# description text from the SNMPTT.CONF or MIB files.
# Set to 0 to disable the $D substitution variable. If $D is used, nothing
# will be outputted.
# Set to 1 to enable the $D substitution variable and have it use the
# descriptions stored in the SNMPTT .conf files. Enabling this option can
# greatly increase the amount of memory used by SNMPTT.
# Set to 2 to enable the $D substitution variable and have it use the
# description from the MIB files. This enables the UCD-SNMP / NET-SNMP Perl
# module save_descriptions variable. Enabling this option can greatly
# increase the amount of memory used by the Net-SNMP SNMP Perl module, which
# will result in an increase of memory usage by SNMPTT.
description_mode = 0

# Set to 1 to remove any white space at the start of each line from the MIB
# or SNMPTT.CONF description when description_mode is set to 1 or 2.
description_clean = 1

# Warning: Experimental. Not recommended for production environments.
# When threads are enabled, SNMPTT may quit unexpectedly.
# Set to 1 to enable threads (ithreads) in Perl 5.6.0 or higher. If enabled,
# EXEC will launch in a thread to allow SNMPTT to continue processing other
# traps. See also threads_max.
# Set to 0 to disable threads (ithreads).
# Defaults to 0
threads_enable = 0

# Warning: Experimental. Not recommended for production environments.
# When threads are enabled, SNMPTT may quit unexpectedly.
# This option allows you to set the maximum number of threads that will
# execute at once. Defaults to 10
threads_max = 10

# The date format for $x in strftime() format. If not defined, defaults
# to %a %b %e %Y.
#date_format = %a %b %e %Y

# The time format for $X in strftime() format. If not defined, defaults
# to %H:%M:%S.
#time_format = %H:%M:%S

# The date time format in strftime() format for the date/time when logging
# to standard output, snmptt log files (log_file) and the unknown log file
# (unknown_trap_log_file). Defaults to localtime(). For SQL, see
# date_time_format_sql.
# Example: %a %b %e %Y %H:%M:%S
date_time_format = %H:%M:%S %Y/%m/%d

[DaemonMode]
# Set to 1 to have snmptt fork to the background when run in daemon mode
# Ignored by Windows. See documentation
daemon_fork = 1

# Set to the numerical user id (eg: 500) or textual user id (eg: snmptt)
# that snmptt should change to when running in daemon mode. Leave blank
# to disable. The user used should have read/write access to all log
# files, the spool folder, and read access to the configuration files.
# Only use this if you are starting snmptt as root.
# A second (child) process will be started as the daemon_uid user so
# there will be two snmptt processes running. The first process will
# continue to run as the user that ran snmptt (root), waiting for the
# child to quit. After the child quits, the parent process will remove
# the snmptt.pid file and exit.
daemon_uid = snmptt

# Complete path of file to store process ID when running in daemon mode.
pid_file = /var/run/snmptt.pid

# Directory to read received traps from. Ex: /var/spool/snmptt/
# Don't forget the trailing slash!
spool_directory = /var/spool/snmptt/

# Amount of time in seconds to sleep between processing spool files
sleep = 1

# Set to 1 to have SNMPTT use the time that the trap was processed by SNMPTTHANDLER
# Set to 0 to have SNMPTT use the time the trap was processed. Note: Using 0 can
# result in the time being off by the number of seconds used for 'sleep'
use_trap_time = 1

# Set to 0 to have SNMPTT erase the spooled trap file after it attempts to process
# the trap even if it did not successfully log the trap to any of the log systems.
# Set to 1 to have SNMPTT erase the spooled trap file only after it successfully
# logs to at least ONE log system.
# Set to 2 to have SNMPTT erase the spooled trap file only after it successfully
# logs to ALL of the enabled log systems. Warning: If multiple log systems are
# enabled and only one fails, the other log system will continuously be logged to
# until ALL of the log systems function.
# The recommended setting is 1 with only one log system enabled.
keep_unlogged_traps = 1

# How often duplicate traps will be processed. An MD5 hash of all incoming traps
# is stored in memory and is used to check for duplicates. All variables except for
# the uptime variable are used when calculating the MD5. The larger this variable,
# the more memory snmptt will require.
# Note: In most cases it may be a good idea to enable this but sometimes it can have a
# negative effect. For example, if you are trying to troubleshoot a wireless device
# that keeps losing it's connection you may want to disable this so that you see
# all the associations and disassociations.
# 5 minutes = 300
# 10 minutes = 600
# 15 minutes = 900
duplicate_trap_window = 0

[Logging]
# Set to 1 to enable messages to be sent to standard output, or 0 to disable.
# Would normally be disabled unless you are piping this program to another
stdout_enable = 0

# Set to 1 to enable text logging of *TRAPS*. Make sure you specify a log_file
# location
log_enable = 1

# Log file location. The COMPLETE path and filename. Ex: '/var/log/snmptt/snmptt.log'
log_file = /var/log/snmptt/snmptt.log

# Set to 1 to enable text logging of *SNMPTT system errors*. Make sure you
# specify a log_system_file location
log_system_enable = 0

# Log file location. The COMPLETE path and filename.
# Ex: '/var/log/snmptt/snmpttsystem.log'
log_system_file = /var/log/snmptt/snmpttsystem.log

# Set to 1 to enable logging of unknown traps. This should normally be left off
# as the file could grow large quickly. Used primarily for troubleshooting. If
# you have defined a trap in snmptt.conf, but it is not executing, enable this to
# see if it is being considered an unknown trap due to an incorrect entry or
# simply missing from the snmptt.conf file.
# Unknown traps can be logged either a text file, a SQL table or both.
# See SQL section to define a SQL table to log unknown traps to.
unknown_trap_log_enable = 0

# Unknown trap log file location. The COMPLETE path and filename.
# Ex: '/var/log/snmptt/snmpttunknown.log'
# Leave blank to disable logging to text file if logging to SQL is enabled
# for unknown traps
unknown_trap_log_file = /var/log/snmptt/snmpttunknown.log

# How often in seconds statistics should be logged to syslog or the event log.
# Set to 0 to disable
# 1 hour = 216000
# 12 hours = 2592000
# 24 hours = 5184000
statistics_interval = 0

# Set to 1 to enable logging of *TRAPS* to syslog. If you do not have the Sys::Syslog
# module then disable this. Windows users should disable this.
syslog_enable = 1

# Syslog facility to use for logging of *TRAPS*. For example: 'local0'
syslog_facility = local0

# Set the syslog level for *TRAPS* based on the severity level of the trap
# as defined in the snmptt.conf file. Values must be one per line between
# the syslog_level_* and END lines, and are not case sensitive. For example:
# Warning
# Critical
# Duplicate definitions will use the definition with the higher severity.
syslog_level_debug = <