When I select the email icon in Acrobat it gives an error message that there is no default email client or that client cannot fulfill the messaging request. However, Outlook 365 is designated as my default email client.
Help in getting this to work would be greatly appreciated.
We're sorry for the trouble you had with Adobe Reader and Send PDF as an email feature, please sign out from Adobe Reader, reboot the machine, launch Adobe Reader and sign back in and check for any pending updates of Adobe Reader from help>check for updates, reboot the machine after updating Adobe Reader and try sending the PDF as an email.
You can also refer and try the suggestions from the following help article Attach to email option is not working | Acrobat DC, Acrobat Reader DC and see if this brings any difference.
Remove outlook from the email client and add it back and choose it as default email client and check.
Reset the Adobe Reader's Preferences once and reboot the machine, to reset the Preferences, refer to the article How to reset Acrobat Preference settings to default.
What is the dot version of Adobe Reader installed? To identify, refer to Identify the product and its version for Acrobat and Reader DC
Let us know how it goes and share your observation.