My broadband connection is usually stable often running for weeks or months without losing the connection.
In the last fews days however the connection has dropped several times.
After a few disconnections I realised that it was happening every time I tried to log in to a particular website (Which magazine).
The connection comes back of its own accord but then shows a security certificate error.
I don't understand why this should cause a loss of connection. Not a big problem as I was on a trial membership with Which and did not intend continuing anyway but I'm just interested to know what was happening.