After inspecting the SSL certificate you can see that the date is invalid for some reason, we saw this on a new Dell server!
The solution is to reset the SSL certificate on the iDRAC with these commands:
racadm -r 192.168.0.120 -u root -p calvin sslresetcfg
racadm -r 192.168.0.120 -u root -p calvin racreset soft
Don't forget to change the iDRAC IP address, username and password to match your setup.
This process takes about 5-10 minutes to complete.