Daily Check-In

[R22120485]

When I try to sign in it says "Requires sign-in count be 15/15 or below", but I haven't signed in for weeks. Please help.

[BrotherVT]

It means that you have completely finished the Daily Sign-In.
At 15 consecutive sign-ins, there is no longer any need to keep going to that NPC.
You have received the final reward for staying on task for those 15 days.