W52P drops call after 38.25 minutes

[Yealink Support]

Hi tas7330,

W52P will drop calls after 38.25 minutes in regular time?
Does this issue happen no matter the other part is internal call or external call ?And what kind of phone does the other part use.
I have checked the trace which was offered by you,and found that the BYE sip was sent out by the other part,and the server transmit the bye message to W52P,then W52P responsed a 200OK to finish the call.
It maybe come out a conclusion that W52P drop the calls passively.
Could you pls make a call to another IP Phone by dialing the IP address,and to see whether the issue still exsit.

Thx