2 of 4 lines on external SIP phone keep dropping

I have found a useful hint in this thread: Extensions unregistering and registering

This is what helped me:

  1. First run asterisk-version-switch and select Asterisk 11; this will result in Asterisk 11.20

  2. Run yum downgrade asterisk11*; this will result in Asterisk 11.19

  3. Delete all extensions and recreate them (save passwords beforehand)

Greetings,
Patrick