This issue usually occurs because of an invalid portal parameter. To resolve this, follow the steps below.
From the dashboard menu, search for and select Administrator Dashboard.
On the Site Manager widget, click Admin Ssettings.
Search for saasHostServer.
This parameter may
be invalid - check the parameter and enter the correct one.
contain an extra space - remove the space.
have a new line added to it that is causing an issue.
If the above looks fine and your URL looks like this 'https://my.corehr.com/pls/coreportal_xxxp' then change it to 'my.corehr.com/pls/coreportal_xxxp/' and then test again.
📌Note: Replace xxx with the client code which you find in the portal url.