Washing machine - lint keeps blocking hose

[CaurnieBred]

Hi there

I have a ~10 year old Bosch washing machine. Twice in the last 4 months I have had an F-04 error. When investigated it turns out that there is lint blocking the outlet hose where it connects to the drain pipe.

Anybody have an idea why this is happening and why the filter on the washing machine isn't trapping it? I have tried to Google but all the links keep pointing me to unblocking the filter itself.

TIA

Maybe you need a new filter - espares will sell them

Is the washing machine filter full of gunk, i.e. is it actually trapping anything? Assume you clean it regularly...