I got the exact same issue. Got it fixed. Software developer at TT can debug it since it is repeatable.
Background:
Spent 4 hours with 5 different TT technical support but no prevail. I flowed the steps that were provided here (remove antivirus, stop firewall, etc.. ) Still asking me for the Licence code and give me error 603. I was going to buy another copy as I had the same issue last year 2019.
Solution:
Remove my saved 2020Tax file from the USB drive and start TT app first then insert the USB with 2020 tax file and it will not ask for License number.
Issue:
The TT app starts up looking to load a 2020 tax files and
If found in PC drive proceed;
Else found in external drive (USB stick, external HD) verify License
- Search their server found it already has max licence active printf("All available activation for that code have been used. Error "errID";
