connecting Apple TV ti the same wifi network after changing wifi pass.

dear all.

recently I was tryin to watch my Apple TV, but it disconnected from my wifi network after changing the pass to this wifi.

i reset Apple TV to fabric setting but it did not help.

I can not change the password which is saved in Apple TV.

it just reporting that the password is incorrect and no option to enter the correct one.. but the code (-100) appearing...

any recommendations?

all apple website procedures did not help..