I hope you're doing well. We apologize for the delayed response and trouble.
Are you still encountering the issue?
Does the error occur when sending a specific PDF file using Acrobat, or does it happen with all PDFs?
Could you share the complete workflow you're using, along with the app or service, such as the Acrobat desktop app, freeware Acrobat Reader, or Adobe Sign web services? Additionally, are you using a Mac or Windows machine, and what is the OS version?
The error message you mentioned typically indicates an issue with the document, account settings, or internet connection. Please try the following steps:
Use a different PDF file.
Sign out and sign back in using your Adobe ID (email).
Switch to a different internet connection and check if the error persists.