Check out the possibilities here. https://www.neptunesystems.com/getstarted/trident/troubleshooting/
I've only gotten this error when my reagent A bottle was empty but the Trident didn't know it (because it had not been Reset.)
Thank you. Found that in my search a bit back and used it to send the ticket. The unit is brand new, so all reagents are almost full. It's hasn't been able to get a reading yet.