Login or password error

Turn off two-factor authentication if it is enabled. You can find it in Instagram mobile app - Profile Settings - Two-factor Authentication

If it didn’t help, make sure that your login and password are correct. 

Both login and password must be entered MANUALLY, do not copy and paste them from a file. 

- “Account name” - you must enter your INSTAGRAM name in this field an nothing else. Make sure there are no extra empty spaces. The easiest way to spot the mistake is to copy the details you use in the cloud and enter them into the corresponding fields on instagram.com

- Carefully check the correctness of your password the same way as for the INSTAGRAM account name

Also check if you received a request for account confirmation. If you did, you must confirm your account using Instagram’s mobile app.

If nothing works, press Edit Account and save your data again. You will be re-authorized. If the issue occurs once more then the solution lies in one of the steps above.

Alternative solution:

Delete your account (purchased license will not be removed) and try to add it again.