I see that you have the Export pdf subscription registered to this account. So there shouldn't be any problem accessing the service.
Adobe Export PDF is an online service that you can access online via- https://cloud.acrobat.com/exportpdf
As well as through the Adobe Reader DC desktop application- Adobe Acrobat Reader DC Install for all versions
You just need to “Sign In” using the email (Adobe ID) under which you have subscription registered.
Also, I assume that you have been trying to access your subscription through wrong application Adobe Acrobat DC not Reader DC?
Please ensure that you are working with Adobe Reader DC not Acrobat DC to access service and "Signed In" using correct email.
For any troubleshooting, refer to- https://forums.adobe.com/docs/DOC-8841
Hope this helps.