No one knows 100% what is going on. But if you have another coil, try it in the tank you have. If it still doesn't read, it is probably your tank.
At that point, it would make sense to replace the tank and try the mod. As long as you haven't damaged the mod, the mod should be fine.
1) Start with the coil (cheapest, most useful option)-- if a FAIL.
2) Get a new tank try on the mod. If it works, you are FINE. If it's another FAIL, it may be the mod, too (stop fiddling with the mod, the more you play with the 510 connection, the more likely you are to HARM the mod. It MAY be okay, but you won't know until you follow all the steps in order. It may be BOTH but at this point, only you doing steps 1 and 2 will let you figure that out.
Good luck, I am also not a "bro" and I don't use that term even with guys, so please, stop calling me that.
Anna