Missing custom UI texture

[dabmasterars]

I used custom .vtf and .vmt files for the user interface of one of my maps. However, the textures do not show up and are replaced with the default black-purple pattern. The custom textures are located in "tf/custom". The directory is specified without mistakes.

Image 1 - Missing texture in-game
Image 2 - Control point properties
Image 3 - File directory

Please, help me fix this issue. Any info is appreciated.