First, be certain the security seal on the box is untampered. In case you find it to be tempered, get in touch with TREZOR support.

What's in the box

1. TREZOR hardware wallet. 2. Recovery Seed card. 3. Lanyard. 4. Instruction paper. 5. USD to Micro USB cable.
Next.
Here are some guidlines that if followed should get your password accepted, each guidline is important:
For example, this would be accepted
!!P3almn!!
(Just an example, do not use)