Hi all.
This is a recurrent problem which afflicts the forum every now and then.
I'm not technical in the least, so I can't tell you what causes it or what the cure is.
The Prof usually makes some adjustments with the hosting service and the problem goes away.
Or sometimes it's a tech or capacity problem with the server host. It's rarely a problem with the forum software itself, IIRC.
Unfortunately The Prof is busy/away at the moment, and I'm not sure about Chris, who is the other forum supremo and technically aware person.
I think this is one for The Prof however, and I'm sure he'll get onto it as soon as he is able to.
But I'm afraid in the meantime you might just have to live with the inconvenience of having to try again later for a few days

It's a good job you're not paying for it, right?

Cheers.
Richard