Getting “Update Failed” is usually an issue relating to WordPress 5.0’s new “Gutenberg” content editor. Most likely it’s not an issue with the editor itself but with something else interfering with it.
- A plugin can be interfering with the new editor. Try deactivating all plugins (except Church Content, which is compatible) in case there is a conflict. If the problem goes away while all plugins are inactive, then reactivate them one by one to determine which is causing the problem.
- Are you using the Sucuri or GoDaddy firewall service? If so (as of writing), their firewall interferes with saving posts in WordPress 5.0. Until they resolve the issue, a workaround is to whitelist your IP with them.
- You can install the Classic Editor plugin to avoid this issue by not using the new editor for now.