This is a very common problem, and what happens is the pipework that takes the water from the gutters becomes blocked with vegetation that literally roots itself in the downpipes which prevents any water from draining away.
Gutters overflow and you can end up with damp walls outside and inside of the house.
We will inspect and when possible, clear any downpipes during our gutter clearing work.
This is one of our more severe cases of blocked gutters. Vegetation had completely overgrown the “Hedgehog” gutter protectors which caused more of a problem. The “hedgehog” system was completely removed for our client to prevent further problems in the future.