iPhone not printing to hp smart tank

Hi I bought a HP smart tank 5106 a few months back, always been brilliant but recently I have been unable to print from my IPhone. No problems with the printer as I can scan and print through the HP smart app. Sometimes it will start the job I’ve requested through my phone but then it occurs an error no errors showing on the printer but it will show up on the app and then other time it just won’t do anything at all. I’ve also tried through my partners phone and get nothing at all. HELP!! Thanks