VMG 3625-T50B Login Error after Firmware Update

cozpolat

I was using a firmware version which ends with G0 and I upgraded it to the V5.50(ABPM.9.4)C0

The problem is; when I reset the router, the default login password at the back of the router doesn't work anymore. I tried different combinations such as 1234, admin, password, etc. but no luck.

What is the root cause of this problem and how can I solve it?

(Please do not suggest foolish solutions like reset it again or push the reset button 5-6 secs… I already know how to reset a router )

Thanks.