Dishwasher waste coming up in bath

[Chalchlo]

So I live in a flat, middle floor, when we turn dishwasher on the waste bubbles up in the bath...now the water is draining VERY slowly from the bath, we haven’t long moved in but I personally don’t think the dishwasher should be plumbed into the same pipes as the the bath should be the same side as the sink etc?
I’ve tried putting a drain unblocking liquid down but not helped, what else can I do?
Obviously I’m not using dish washer anymore

I had this in one house and plumber said it was because the pipes I had couldn't cope with a dishwasher and everything else.

Not sure if this will help you but I wanted to reply!

Yeah I think it’s prObably the same here! I just need to get it unblocked because of the bath not draining water!! Not bothered about not having dishwasher

you have a blockage, or bad pipe design, or both.

A dishwasher is usually in the kitchen and plumbed into the sink waste.

How old is the building; and how old is the plumbing?

Post some pics.

Has anybody ever put cooking fat down the sink?