Cisco 3905 rejected

[Hythim Ali El Hadad]

Hi

We have a problem with our 3905 IP Phones. When we try to change configuration. The phone move to rejected status and couldn't register to our CUCM 12.5

I found many many tftp timeout on the phone log web page

When I do capture on the phone port, I didn't find any tftp request into the CUCM going out from the phone

I try to reset the CUCM . and try factory reset the phone with no luck

What could be the issue

Thanks

Haitham