Remember me?

[LG17]

Last week the site logged me out as it does every so often, but it wouldn't let me log back in.
All I got was gobbledegook. I should have kept the messages but didn't think at the time.
I had to change my password, which I did and logged on.
Now, even though I have ticked the 'Remember me' box every time I leave the site it logs me out and I have to log in again.
Is that likely to be something at my end or is it the site?
Thanks.