Used to do Twitter on MacBook Pro, now can't

[newbph]

Did Twitter for many years via MacBookPro.
Got a desktop Mac and started using that instead.
Want to take laptop on a trip. Twitter says "There was unusual login activity....enter phone number or user name"
But can't, because the form keeps blinking.
Not flickering like defective screen, just deliberately blinking so the form isn't stable long enough to fill in the information. Please help?

 

[Fried egg on toast]

There's a free app called Friendly For Twitter that I use on my MacBook.You can also use it for Telegram and some other social media platforms too. Never had a problem with it 👍