Outlook 2016 with Exchange on Windows 7

[InterLinked]

I've been really struggling with this issue lately, so I'm wondering if anyone else has been having a similar issue.

I use Windows 7 as my primary OS, with Office 2010 as my primary office suite, and for a long time, until mid last year, I used Outlook 2010 to access my calendar and contact. I use Roytam1's MailNews as my primary email client, as Outlook sucks at actual email, but I love it for Exchange access to my calendar/contacts, for a personal Microsoft account.

At some point last year, 2010 stopped working due to the basic authentication shutoffs that Microsoft was doing 

So after cursing them to the moon, I installed Outlook 2016 on my PC, keeping the rest of Office 2010, so I could continue to access my calendar. At the time, it was a necessary evil to function.

I hadn't used that machine in a little while due to traveling and such, and when I came back, I reimaged the machine as part of joining it to a domain and getting a fresh setup. I found that Outlook 2016 would no longer connect to Exchange accounts. With suitable updates, it can connect using IMAP just fine, but I don't want IMAP; I use a better client to do IMAP. It must be Exchange.

I've now spent probably 10 hours troubleshooting what could be the issue - software updates, network issue, DNS, TLS negotiation, etc. I've looked into everything. Finally found a working version of Outlook 2016 at another site and installed verbatim on a Windows 10 VM here, and it worked. But when I did the same on a Windows 7 VM, it did not.

Microsoft obviously says that Win7 is not supported, blah, blah, blah, but it was working just in the past couple months, so I think it's unlikely that something has changed in that time.

Would anyone happen to know what the missing puzzle pieces might be to making this work? Since the only difference here is the OS, are there certain files that differ between the two versions of Windows, that could make a difference?

Because Outlook 2016 is the newest version supported on Windows 7, this is an issue that is bigger than just Outlook 2016, it is literally about being able to access my calendar using ANY version of Outlook, on Windows 7. It is unbelievable that Microsoft is deliberately screwing with people as much as they can. I wish I could send them an invoice for all the time of mine they've wasted here!

At some point I'll probably be forced to set up an on premises Exchange server, just so I can have calendaring access (it must be accessible from multiple machines), but I wasn't planning to do that this year. I'd like to keep using Outlook 2016 as long as it's supposed on any OS (which it should be until 2025).

Any help here would be a lifesaver, thanks!

[InterLinked]

Okay, knew it was something I had to tweak, this was the fix: https://support.microsoft.com/en-us/office/outlook-stops-connecting-on-windows-7-and-legacy-windows-versions-55263b47-921b-4ed8-98fd-c90fb326379c

Applied this via Group Policy to all machines so I never have to worry about this again!