I would like to change our ISE FQDN. What issue could arise by changing the ISE FQDN? Say from Host.A to Host.B. I would like to do this in order to apply a certificate we now have.

Received this message today and not really sure what caused it and why. Has anyone else experienced this? We have not made any changes or upgrades lately, C370 ESA. Thanks in advance  The Critical message is: An application fault occurred: ('session...