Other users have noted that ink and especially gloss enhancer can end up inside the printhead compartment and on the metal contacts (where the printhead interfaces with the carriage). Try cleaning off the contacts with distilled water on a microfiber cloth or no-lint swab, then re-seating the printhead. I haven't had the problem myself, though I did have to replace one printhead shortly after I got the printer after a head crash due to incorrect paper preset selection on my part. Initially the printer told me to reseat the printhead; after a few tries it gave up and told me to replace it. So I did, and all was good.
Hope this helps.
Thanks, ... I'll work on cleaning the contacts tomorrow.
I'm a bit fatigued from stressing over this.
Time to open a bottle of wine and chill for the evening.