Problem with cached images

[weinstoc]

Hi, I hope someone can help me. We installed, a long time ago, on our 3.8 forum something that helped with image caching. It would store the images in a large directory (e.g., /images/cache-img/) and retrieve them from there.

Last night something changed in our firewall environment and it seems that new images aren't successfully being uploaded any longer. The previously uploaded images are still available through https://forumserver.twoplustwo.com/cache-img/foo.jpg for example but uploads since yesterday fail.

I'm not sure where to begin to look for this. I've asked our server provider to look at what changed in the firewall (there were some changes) and I guess it almost has to be this...but I'm hoping someone here can shed light on this for me.