Upgraded to fiber, new network. Now Facebook blocks login

For past few months Facebook would ask me to verify my identity on another device about one in every 3 logins. Not a problem.
Today upgraded to fiber connection with new network. FB ask me to verify elsewhere again but denied verification claiming another person accessed my info.
Also, I no longer receive option to verify via email.
Any tips? Thanks.

I would suggest contacting Facebook's support.

Try using gmail, if you haven't already.