no idea.
ive not used this model but do have other coolfires so this is just guesswork.
your screen should look like this
how old is the mod and has it been used continuously or been sitting in a draw for months.
has it worked previously with same tank and this message just appeared overnight or have you added a new coil and then you get this message. if so could just be a naff coil. it happens with all makes of coil. ive had 3 crap ones out of a box of 5 but a different make.
apart from that it might be time to get a new mod as this one is ready for the bin.
I’ve only had it 2 months I just went to use it yesterday morning I’ll try changing coil thank you will let you know just with the shop being closed can’t talk to guy who sold it