Put it in the drum instead of vinegar. Mold and coatings disappear, and the washing machine will smell wonderful!

Moisture, lint, hair, and detergent residue can accumulate inside the gasket folds.

Cleaning and drying the gasket regularly can help prevent recurring odors.
Can I just pour something into the drum and fix everything?

No.

A washing machine has several areas that can collect residue:

Drum
Rubber gasket
Detergent drawer
Pump filter
Drainage system

A single “miracle mixture” cannot reliably solve every type of washing-machine problem.
The Best Alternative to Vinegar Isn’t Always Another DIY Hack

Citric acid can be effective at dissolving mineral deposits, but it should not automatically