Correct. ProSeries needs 32 bit. You may be able to uninstall Outlook and reinstall it as 32 bit.
This is the same solution that worked for me. Actually, MS Office needs to be uninstalled as 64bit and re-installed as 32bit.Then the client organizer e-mail function will work.
I tried a half dozen other solutions and this is the only one that did the trick.
I have an Outlook support contract with Microsoft so the agent helped me through it. I believe that with Office 2016 Home and business, you will need a Microsoft account to log into to get the software download and then license it again after installation.
After all of the testing I did around this problem, and downgrading my MS Office to 32bit (from 64), I found a configuration item in ProSeries Professional for 64bit e-mails. I had user rights permissions that I was trying to fix and found this setting under Tools/Options/General/Email Options - Use 64-Bit E-mail Client. Maybe this is the correct fix for the problem. I may be able to test it on one of my workstations, but the server I use myself is working so I don't want to mess anything up right now. It's time to make donuts.