Sip register failed after power outage

[mariyah]

Phone types: Fanvil X3s and X3s Pro.
The latest firmware is installed on all phones. They are all working well.
Power outages often occur, so our phones go dark, and when power is restored, they display SIP Register Failed. I don't understand why this occurs.
It sometimes works fine after rebooting the phones, but if left at the Sip register failed state for a day or two, the public IP seems to get banned, as it won't work until you use a different public IP.

The second question is, how can I determine if an IP is banned from 3cx and how do I unban it from the portal?

 

[Saqqara]

within the management console, click on ip blacklist which is in middle panel.

how are the phones provisioned - lan, stun or sbc

 

[mariyah]

Thank you for your response
The IP blacklist does not contain any Denied IPs (they only contain the list of Allowed IPs that I have added)
Phones are provisioned via STUN.

 

[VasilisV_3CX]

Hello @mariyah,

Please read this link and provide the following details: https://www.3cx.com/community/threads/information-to-provide-when-requesting-help.67558/