Cisco Term Sessions

Do you have multiple people logging into that thing? Do you have time-outs configured? It's possible you've tied up all the term sessions.

Checking for line types:

snmpwalk -v 2c -c $community $deviceIP 1.3.6.1.4.1.9.2.9.2.1.2

Checking to see if they are active or Idle:

snmpwalk -v 2c -c $community $deviceIP 1.3.6.1.4.1.9.2.9.2.1.1

Clearing them if that's the case:

snmpset -v2c -c $community $deviceIP .1.3.6.1.4.1.9.2.9.10.0 integer <LINENUMBER YOU WANT TO CLEAR>