Recently updated to Joomla 5. Everything went smoothly, except for the template styles give an error when editing. When I go to System > Site Template Styles > T4 Template Blank (Default for all pages), I get the following error:
403 You have been blocked due to a security rule on this website.
Template change I make do take effect, I just am used to seeing the site preview in this pane instead of an error. When I try to upgrade to the T4 template for Joomla 5, I get the following error:
JInstaller: :Install: Can't find Joomla XML setup file.
The Joomla package cannot be installed through the Extension Manager. Please use the Joomla! Update component to update Joomla.