What i use: Yeastar S20 & 4x Yealink T48S & 1x Yealink W56P
With Firmware 188.8.131.52 outgoing calls drop after 30 seconds.
Back to the Firmware 184.108.40.206 everything is OK again.
I didn't change any other settings on the S20, the phones or the network - i just updated the firmware.
Is there a known bug?