Hope you are doing well and sorry for the trouble.
AcroCEF is an integral part of Acrobat. AcroCEF takes care of HTML based components of the application like(Send for signature, Send and Track, fill and sign, Document Cloud, etc).
Please make sure you have the latest version 21.01.20145 of the application. Try to update the application from the help menu and reboot the computer once and see if that works. Go to Help > Check for updates.
Also, please try the following preference setting and go to Edit (Win), Adobe Acrobat (Mac) > Preferences > Page Display > Under Rendering Uncheck 'Use Page Cache' > Click OK see if that helps