I keep changing the system wide default profile cover image, but as soon as I click the "Save Options" button, the cover image returns to the default image. I've also tried changing my own personal cover image, but that one also returned to the default image.
works fine in our test websites.
Please try it again, use other images.
Make sure the images are not too large.
Check database errors in wpForo > Tools > Database Tables admin page.
Also, please press F12, go to the "console" tab and take a screenshot of red marked errors.
Thanks Robert. I've reduced the image size now. It's now 1000 x 354 pixels. The image size is 180KB (JPG).
I've checked the databases, and the screen says "No problems found in database".
I've tried another image, but the image still doesn't get saved.
I'm not sure where you want me to press F12 in order to access a "console" tab. How would I access that?
It seems your website is installed in WordPress.com hosting service.
In any case, please try to disable all plugin, especially the JetPack and all kind of CDN/Cache solutions. Then check it again, if the problem is resolved then activate all one by one and check after each plugin. This will let you find the conflict maker plugin.
If the issue is not fixed yet, please send the admin login details to support[at]gvectors.com email address, we'll check it within next 1-2 days.