SharePoint Office Document keeps asking for credentials

Office document which is stored in SharePoint keeps asking for credentials. No matter if you are working in a SharePoint library or just try to export a list to excel. It just keeps you busy by asking for your login username and password. By the way it was a SharePoint 2016 which used Form based authentication (FBA) where the client integration didn’t work.

Suppress Modern Auth for Office Clients

The solution is really simple. But it took a long way to get there. Finally we came to the solution thanks to this blog post.
In this post it was the suggestion to use this powershellscript:

$sts = Get-SPSecurityTokenServiceConfig
$sts.SuppressModernAuthForOfficeClients = $true
$sts.Update()

And this was exactly what worked for us. Now our user could open Office documents and export to excel. We have to mention that this helped user who had Office 2016. More details can be found in the post i mention above.

After that of course you do an iisreset and restart of the sharepoint timer service.