Kitchen smells gross when washing machine fills up

[sasscass]

I put the laundry in and turned the washer on, the washing machine was filling up with water ready to wash the clothes and a foul smell engulfed the kitchen. It must be coming from the pipes, the washing machine itself doesn’t smell foul. The washing machine is right next to the sink and I think the smell is coming from the sink.

What’s causing this and how do I solve this?

Let me add, it smells like rotten eggs and kinda like sewage

This is pretty common ime

Start with putting boiling water and some bleach down the sink drain.
When the shops open, buy some drain unblocker and use it regularly