I currently have the issue above, after moving a site from localhost. Trying everything I can think of, I still haven't fixed and can't login to the admin panel because of this error. Never had this issue in the past.
ProcessWire: ProcessLogin: This request was aborted because it appears to be forged.
DEBUG MODE BACKTRACE ($config->debug == true):
#0 /var/www/vhosts/xxxxxxx/httpdocs/wire/modules/Inputfield/InputfieldForm.module(186): ProcessWire\SessionCSRF->validate()
The only thing that changes it is turning off CSRF, which is not what I want.
EDIT: Typically found the issue right after... I had a cloudflare worker which modified the 'Set-Cookie' header.