Can't create a project in Workforce

[SushilPradhan]

Installed and configured workforce for ArcGIS Enterprise 10.6. When tried to create a new project, am getting this error message. My SSL certificate is still valid and the same certificate is being used in the enterprise configurations, i.e. portal, arcgis server. Just couldn't figure out this one what the issue is, please let me know if anyone has any suggestions. Looked at the similar threads, but still not very helpful for me. Thanks