Very Simple fix here:
What you have is a standard 1-1/2 PVC slip compression joint "waste & overflow" kit.
Obviously the TEE section has slipped down which has put the drain arm out of alignment with the TEE and is making it difficult to properly secure the joint.
To correct the problem:
1. loosen the slip nut on the overflow riser
2. Loosen the slip nut on the Trap Adapter.
3. Slide the Sanitary tee section upward slightly until it is in proper alignment with the drain arm.
4. Tighten the compression nut on the drain arm.
5. Tighten the compression nut on the overflow riser.
6. Tighten the compression nut on the Trap adapter.