Exchange 2010 to Exchange online hybrid migration

Hi, we are starting an O365 migration from an on-prem Exchange 2010 server. I am trying to create the migration endpoint and get the error below.

We couldn't detect your server settings. Please enter them. AutoDiscover failed with a configuration error: The migration service failed to detect the migration endpoint using the Autodiscover service. Consider using the Exchange Remote Connectivity Analyzer ‎(‎ to diagnose the connectivity issues.
Remote MRS proxy server:
The FQDN of the Exchange server that the Mailbox Replication Service (MRS) Proxy is on. Autodiscover tests pass. https://<exchange fqdn>/EWS/mrsproxy.svc connects. But, I cant get the endpoint to create.
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Vasil Michev (MVP)Commented:
Make sure your firewall is not blocking the connection and you have a valid 3rd party certificate assigned. And/or try to manually create it, bypassing autodiscover.
Here is the very similar issue with suggested answer-
mac carterCommented:
Please have a look on below given earlier discussed threads having suggested solutions might helps you in your circumstance.

Hybrid migration error

Autodiscover for Exchange 2010 SP3 Hybrid

In general, the Autodiscover DNS record needs to be pointed to on-premise Exchange Client Access server in a hybrid deployment. For detailed information, I suggest you run the Exchange Server Deployment Assistant at expend the Configure Hybrid Deployment Prerequisites option, and click Configure DNS records. By doing so, Autodiscover can work for both the Office 365 users and the Exchange On-premises users.

Also have a look on this informative article which describes Exchange Remote migration endpoints in a Hybrid scenario:

Hope it helps you!

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