"This phone was removed from your account. Link it again with a new code." means the phone isn't linked to your account any more. That happens when:
- the phone was removed on the website under Phones (by you, or by anyone signed in to your account),
- you tapped Remove this phone in the app,
- or the phone wasn't used for a long time and its sign-in ended.
Protection on the phone keeps working; only your plan's features (such as Deep check) stop.
To link it again, create a new code on the website and enter it in the app (see "Link your phone to your 1kr account").
If you didn't remove it, someone else may know your password: change it on the website under Security, turn on two-step sign-in, and check Phones for phones you don't recognise.
"Accounts aren't available in this version of the app." means this version of 1krBlocker was built without accounts. Install 1krBlocker from Google Play.