SharePoint 2016 replies with wrong url (Outlook 2016 calendar)

Question

Hi there,

Let me describe my environment first.

I have a SharePoint 2016 Farm set up with two Front-End servers with Cache and two Application servers with Search. There are two Web Applications:

• Central Administration v4
• Our main portal

Our main portal is accessible via portalsearch.contoso.com (default zone) and portal.contoso.com (internet zone).

Search accesses the web application through the default zone using NTLM authentication. Users access the portal via portal.contoso.com using ADFS.

I’ve been encountering two issues for the past three weeks since we switched the zones. Previously, portal.contoso.com was in the default zone, and portalsearch.contoso.com was in the intranet zone. This configuration caused issues with the search functionality.

After taking over the project, I switched the zones to restore the search functionality (crawling on the default zone).

Now, here are my problems:

When users connect a SharePoint calendar to Outlook via a button, Outlook prompts for credentials with a grey Windows authentication window. The credentials are being requested from portalsearch.contoso.com instead of portal.contoso.com. But this will not work, since the user are not allowed to access the portal via Windows authentication, only via ADFS.

When a user sets an alert on a SharePoint list and receives an alert email from email address removed for privacy reasons, the hyperlinks in the email point to portalsearch.contoso.com instead of portal.contoso.com.

Did I make an error while switching the zones?