Win XP Pro SP3

Thunderbird 52.9.1

eMail access

I have several eamil accounts: hotmail, outlook and damned gmail.

I open Thunderbird and immediately get a request from gmail to allow
access by Thunderbird for one of the gmail accounts.
I enter the password and thunderbird now has access. Great ! But why !

Next I proceed to another gmail account in TB and am denied access.
This time tb is asking for the password. I enter it and check the box
to remember it and it fails.
I repeat and it fails.

So I proceed to another gmail account and same thing happens.

I have a password bank so I know the password is correct !

All other brand accounts have no problems and are accessible.

These were all working a few months ago !
I had no need to use this PC recently but now I do.

Also, gmail, for another account says it was suspicious attempt,
whatever that means and wanted to verify using a phone number to send a
text to.
unfortunately, my cell phone is not with me. so I am locked out of that
account because of gmail !!!

Pertinent Suggestions please.