^^^ I've answered your question on the basis of 'Law' (since that's where you've posted) on the assumption that the machine has reached a stage in its life where it simply can't do its job properly without, say, needing a new door seal. I'm happy to stand by my answer based upon that assumption.
However Tony and Barry have (wisely) approached the question as if it had appeared in AB's 'How It Works' section. In the same way that, for example, you couldn't reasonably complain to your landlord about your loo smelling if you'd never put any bleach (or similar) down it, you can't expect your landlord to fix things if you've not carried out the necessary routine maintenance with a washing machine. So, if you've not actually cleaned the seal, that's clearly the first place to start before you consider hassling your landlord!
https://blog.fantasticservices.com/how-to-clean-a-washing-machines-rubber-seal/