78xx IP phones have calls dropped &re registered again And shows on the screen (REG send failure :REGISTER

[Ahmed habib]

Hello,

I have urgent problem

Users with 78xx IP phones have calls dropped & registration failure  and phones re registered again

And shows on the screen (REG send failure :REGISTER)

This happens randomly all the day for 3 or 4 users

I upgraded the firmware to  but the problem still exists

[zeuscyril]

hi 

check form network side any packet drops or errors in the switch ports.

please share cucm and phone version