Extensions/Template Conflict
Using Shaper_stellar template, was working fine before SPPB update, yet it works with some pages
Cloudflare service
Not using
Enabled Mod_Security on your server
Not installed
Update template framework
Not needed
Update JCE Editor to last available version, above 2.6.19+.
JCE 2.9.1 installed
After installation clear browser cache.
Done
Update SP Page Builder Pro to the last available version (3.1+).
That's the issue cause ;-)
Clear Joomla cached files (System > Clear Cache > Clear All).
Done
Enable GZip compression in Joomla! Global Configuration.
Was already enabled, done
PHP version should be at least 5.6. We suggest using PHP 7.1 or 7.2 or PHP 7.3.
Using PHP 7.4 here, working fine with previous SPPB version
If you have problems with PHP 7.2, please use the lower version.
does not apply
Disable all additional plugins which uses JQuery on front-end, for example, for Cookies plugins.
it's a clean system, nothing installed
Login on the front-end as administrator and check again.
Done
Check also from the different template set as default to find a source of problems.
Same problem with all templates
Disable protection from the Firewall component (Akeeba Tools Pro).
Not installed