Sorry for the inconvenience caused to you.
Can you please share the Reader version you are working on and OS details?
It would be very helpful if you could share the exact workflow and a snapshot of the error message?
Meanwhile, please use Export PDF service in 'cloud.acrobat.com'.
I have had this same issue for the last few months. I paid for the service in February 2016 (annual subscription) and was only able to use it for a few months.
This is the error message I get.
Also when I try to access my account from here, I get the screen below:
Can someone please help me?
Try to Sign-out from the application and restart your system.
Then Sign-in and check if you can use Export PDF tool.
You can also try to export PDF online here: https://cloud.acrobat.com/exportpdf
Could you please confirm the dot version of Adobe Reader application and OS installed on your system.