yes, it usually happens when i do too many operations at once, i.e. open pages with many images and then click reload. But I have not had this problem for 2 weeks now
Thanks guys. I'm glad it's not just me. I was wondering if my IP address had been blacklisted somewhere or something along those lines.
In my case, I don't think that it's to do with opening too many pages, or pages with lots of content. I'm pretty sure that I've had it happen when opening just 1 or 2 pages in the past.
Today I've opened 5 pages at once with no problems at all.
There were several (D)DOS attacks recently, and I've added a protection module that limits the number of connections per ip. Simply refresh the page if this error happens.
I also get it from time to time when I open multiple tabs at once.