I paid for a PDF convert subscription and I can not use it. The online chat and calling customer service was no help. I sign in and then when I try to convert a file I get an error message "An Error occurred while signing in"
Please try once to sign out and then relaunch the application.
Then sign in with your Adobe ID and check if you can export PDF or not.
Also, you can export PDF online here: https://cloud.acrobat.com/exportpdf
Check if you can export file here without any issue.
Let us know if you still experience the issue.