There is the black texture under the far sea. I didn't change the material.

In my client, the console constantly dumping out the below errors:
[SndOperators] Operator Error: Event port.Pier: vmix_start_vmix_8track has empty vsnd string
[SndOperators] Operator Error: Event port.Outside: vmix_start_vmix_8track has empty vsnd string

And the far sea is totally black (only a small area with ships is normal).

I used de_anbis' water material. That's just how it looks. The transparency effect occurs because the underside of the 3D skybox uses a black material.

it looks like the water has a problem because the boats just float on the air