Similar recent topic:
You have to delete the offending certificate and restart. Ignition will make a new one, with another three-year validity period. Use the remote's UI to accept Ignition's new certificate.
Consider upgrading to take advantage of the option to create longer validity periods in the new UI.
{ v8.0.10 is ancient and buggy and hasn't been supported for a couple years now. This isn't the only reason to upgrade. }