I also faced the same problem when I was testing it with Azure AD
When you map attributes in okta for Azure AD (as per https://help.okta.com/en/prod/Content/Topics/Provisioning/azure/azure-map-attributes.htm) Make sure to check that the External URL name does not have “.” at the end. cause if you directly copy and paste it will include “.” also in URL and it will give an error.
Let me know if it worked for you or not.