That was a known issue when a printer was either upgraded to Connectkey 1.5 (The version you mention is the first 1.5 release) without wiping the data via an Altboot no data backup, and also when it was updated correctly, but a clone file was used to restore settings from a Connectkey 1.0 release.
Best bet is to upgrade to the latest with the tool method from this link. That should clear the issue, and at the same time take it to the absolute latest firmware without data loss.
If the upgrade fails, you would need a tech to do the Altboot no data backup no clone method to that same new firmware, that will 100% fix the issue, but involves complete data loss, the entire machine would then need to be setup from scratch, so it isn't something you want as a step 1.