If the front panel ALARM LED is lit and only one port is in alarm, that means that port is configured either under the DIAL PLAN or in the DEDICATED MAPS. If you remove it (delete it) from those locations the alarm will clear.
Now when you go under the MODULES and look at the ALARM STATUS, it will always show LOS and RED because nothing is plugged in, but the front panel will not show an alarm and when you look at all the modules, it will not show an alarm.
Hope this helps,
Patrick