Thanks for raising this issue with us.

It would be great if you could share more info about the environment, installation and issue.

Please update application via Help->Check for updates to be on the latest and safest version of Acrobat/Reader and restart the machine.

If the issue still persists, we would require the following information to understand the issue better:
-> Environment/Platform/System information
-> Application(Acrobat) version
-> Does other views like Document Cloud, My Computer, Save As Dialog, Send and Track, Send for Signature, etc. are working as expected?
-> go to Activity Monitor(MAC) and check whether a process named "AcroCEF" is running or not?
If running, is it in a hanged state? if yes.
Please select process-> click setting icon above to expand the drop-down options -> take Sample process and Run Spindump and share both with us.

-> Check if Acrocef.exe is crashing [Go to Activity Monitor(MAC) -> observe PID of AcroCEF processes, it changes], Go to Console -> User Diagnostic Reports
Share reports name starting with "AcroCEF".

-> Kindly share the contents of following locations :
/Library/Application Support//Adobe/Acrobat/DC/WebResources/Resource0
Content of Acrobat
/Contents/Frameworks/AcroCEF Helper
/Contents/Helpers/AcroCEF/AcroCEF

You can share logs/dumps/sample files with us via Adobe Send https://documentcloud.adobe.com/link/send/ or any medium you are comfortable with.

Please let us know for any help/assistance here, we can schedule a discussion as well to look into the issue in detail.