T38G pickup handset doesn't answer the incoming call

[Wilson_Yealink]

Hi Daniel,

I think somethings SIP server can't deal with too many BLF SUBSVRIBE message at the same time. So it will lead to the phone become slow.

Please change the SIP Session Timer (seconds) T1 to 1 or 2 and have a try. Access to the web GUI->Account->Advanced tab, change the value in the SIP Session Timer (seconds) T1 field. And you need to confirm the correspoding account you used. Just like below picture.

Click confirm to accept the change.

You can disconnect one or two EXP38 then have a try to confirm whether phone is slow or normal.
May I know what is your PBX server now?

thanks