Arcgis Portal Upgrade Failes with error Web Server SSL certificate does not match list of certificates

[PhilipHughes]

Trying to update my working 10.5.1 production Portal server and installs and brings up the Continue upgrade.  Click and all seems to work and then get a popup error about SSL certificate.  On checking the portal logs there a severe error "Migration failed. Web server SSL Certificate does not match list of certificates. Web server SSL Certificate does not match list of certificates."

Can uninstall 10.6 and reinstall 10.5.1 and all works perfectly again.

System is running on windows 2008r2 (fully updated with MS patches)

[JonathanQuinn]

This is a bug:

BUG-000112474 - The Portal for ArcGIS upgrade fails with the error, "Web server SSL Certificate does not match list of certificates."

It's fixed at 10.6.1. The workaround is to revert to 10.5.1, (uninstall 10.6, reinstall 10.5.1, restore the content, db, and index folders under upgrade-backup), sign into Portaladmin, go to security > sslCertificates > update and simply hit the Update button, and then upgrade to 10.6. You may want to reach out to Technical Support to go through this.