Take the coil out and look at the bottom, there's a little black o ring/seal, sometimes wire can stick out of that giving you the error message,
If that's not the problem, unscrew the tank a little bit, try to fire it, if still get same error unscrew further till it can finally read your coil.
If that doesn't work check your 510 on the mod, see if you have some juice or condensates droplets of water in there. Same for the bottom of the tank. If you have a other tank try this one.
If all that doesn't work contact the vendor you bought it from or the warranty department and have them ship a replacement or repair it. If you say that your coil is screed in straight and proper not loose or tilted, then most likely there could be an issue with your 510 connection.