Sketchup keeps asking for sign-in

Good day.

Sketchup Pro 2021 keeps asking for login.
Same with LayOut.
I will login, it will work for a couple of days, and than on program start, it will prompt me to sign in again.

Any way to remain permanently signed in?

If SketchUp was not installed correctly all kinds of unexpected permission issues can arise.
Perhaps your setup is not saving details successfully.
If you do the following it will do no harm, and it might resolve your issue…

Whilst you are logged into Windows using your normal user-account, ensure that SketchUp & Layout are not running.
Find the SketchUp installer’s exe file - usually in your Downloads folder ?
Select its icon, right-click > context-menu > “Run as administrator”
When prompted choose ‘Repair’
When it’s done restart SketchUp and see if it’s helped.

Doing the Repair will not affect any of your customization/extensions etc.
But it might let SketchUp save data useful to logins and preferences etc.

Never ‘Run’ an installer’s exe file by double-clicking it - even if you are an admin it is not the same as running it properly…