Hybrid Migration to Exchange Online SSL Error

[ThomasDietzius]

Hello!
I'm struggling with this SSL error message during the On-premises to Microsoft Exchange Online Migration.

Let me give you some information first:
- Exchange 2013 - 15.0.1497.2 CU23
- AD Sync in place and working
- TLS 1.2 is enabled
- On firewall SSL inspection is off
- Basic Auth activated on the WinRM
- MOST IMPORTANT: this have being working for days! We have already migrated a few mailboxes for testing and was working. Now we needed to migrate all the others, it stopped working. No updates or reboots of the Exchange servers have being done.

Do you guys have any ideas?
Thank you!!

[#2 · Accepted solution]

So, if that can help someone facing the same issue... I don't have the answer why it didn't work when running the Hybrid Wizard from the Exchange Servers (Windows 2012 R2 updated to the latest update).
But installing the Wizard on another VM with Windows 2019 worked. I don't know what to get from that, but for me it's enough... I can now proceed with the migration and I'll be happy to get rid of those Exchange servers.

Thanks!