After the installation of the Okta MFA for Active Directory Federation Services (ADFS) Plugin you receive “An error occurred” when there should be a prompt for MFA.
This can have of course a variety of reasons, if you don’t find anything in the logs – be sure to enable TLS 1.2 on all ADFS servers.
See here: https://help.okta.com/en/prod/Content/Topics/Miscellaneous/okta-ends-browser-support-for-TLS-1.1.htm
Especially: “Enable TLS 1.2 on .NET”.
This is most of the times overlooked and is an easy fix 🙂