When installing Office 365 Professional Plus on a PC, the wizard automatically connects the email accounts to Office 365 easily. However, if you want to add an additional Microsoft Exchange on-premises account, there may be an issue where the Mail applet in the control panel does not work.

This appears to be cause by incorrect registry settings. Uninstalling Office 2013 and Re installing it appears to solve the problem in most cases. Settings appear to be retained and do not need to be reconfigured.