Transaction

[Error Code: 1101] error caused by: 1 error occurred:
	* transaction execute failed: [Error Code: 1101] cadence runtime error: Execution failed:
  --> 513f31272b4777e6eee3a837382dde4e8866f9000b3ba681dbd3a1fc11375e68:12:46
   |
12 |                         self.transferToken <- collectionRef.withdraw(withdrawID: tokenID)
   |                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: unexpectedly found nil while forcing an Optional value
  --> 4cf4c4ee474ac04b.MLS:86:25
   |
86 |             let token <- self.ownedNFTs.remove(key: withdrawID)!
   |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^