Can't connect securely to this page comes up when try to access office365 through exchange server 2016 ecp

Question

Hello, all

I am trying to configure hybrid environment exchange server 2016 to office 365.
Most of procedure have been completed so I have to verify if it's normally set up with testing user mailbox migration to office 365.
When I click modify button in the Hybrid tab of ECP, below error message shows up.

"Can't connect to securely to this page"
This might be because the site uses outdated or unsafe TLS security settings. IF this keeps happening, try contacting the website's owner.

All configuration value in the IE was also tried to reset.
Edge, chrome was tried.

What else I should do for solving this problem.

thanx.

Answer 1

Hi @Anonymous ,

1. If you directly click the "Office 365" button to switch EAC, can it succeed?
   
2. Please check whether you enable the TLS 1.2 in IE, then clearing the browser cache and try again.
   Path: Open the IE-> Internet Options-> Advanced-> Security->Using TLS 1.0/1.1/1.2.
3. What’s the specific version of your Exchange serve and Windows Server. Please make sure support and has been enabled TLS 1.2.
   For more information: Exchange Server TLS guidance, part 1: Getting Ready for TLS 1.2 and Exchange Server TLS guidance Part 2: Enabling TLS 1.2 and Identifying Clients Not Using It
4. Please open IIS and check whether your default site is bound to a certificate purchased from a trusted third-party CA. This certificate assigns at least SMTP and IIS services. And then please reset the IIS.
   

In addition, you could following the stesp in this article to migrate user mailbox: Move mailboxes between on-premises and Exchange Online organizations in hybrid deployments

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