After revisiting a site that I have not accessed for a few weeks, I get this error.
ConfigStorageReadException: The configuration file "system.core" is not properly formatted JSON. Contents: <pre></pre> in ConfigFileStorage->read() (line 1041 of /home/rnetcouk/public_html/core/includes/config.inc).
This prevents access to any page on www.r-net.co.uk
I suspect it may have been triggered by insufficient space being allocated on shared host, but that is now fixed.
OK, I'm not the best person to offer advice on this problem and I may be stating the obvious (or I might be completely off base), but I would GUESS that your configuration files have been corrupted somehow. That is where I would start looking.
Do you have backups of the config files?
Do you have config (or any of your code) in GIT?
Do you have another Backdrop site that you can compare the config files against?
(Just spitballing here).
I agree with stpaultim. The error message suggests that the configuration file system.core.json has been corrupted. I would try to restore the file from a backup. If a backup is not available then you could copy the file from another Backdrop site, although you might lose some settings.
Thanks a million!! I had a very similar site and copied the config folder across.
I suspect the config file was corrupted because of limited space on the server.