The apartment itself was ok, nothing wrong with it. The biggest issue was that it was hard to find a phone number for the hosting company. Usually we wouldn't need it, but in the morning of our checkout, the elevator was not working and the fire exit from the building/staircase did not work and we've struggled quite a lot to open it.
We've almost missed our train from Porto but more importantly, it's a safety issue if there is no emergency way out of the building.