Diagnosing something unfamiliar.
READ IT PROPERLY
Errors usually name a file, a line, and a specific problem. That is most of the diagnosis.
Do not skip past the detail to the general shape of the message.
ESTABLISH WHERE IT COMES FROM
The browser, from a failed request PHP, from the application The database The mail system The web server
Each has its own log.
THE THREE TESTS
Does cPanel load? If yes, the server is running. Does a plain test file load? If yes, the server and files are fine. Does it work on mobile data? If yes, your address is blocked.
WHAT CHANGED
Almost every new error follows a change: an update, an edit, a new plugin, a migration, a PHP version change.
Reverse the most recent change and see whether it resolves.
ISOLATE
Disable plugins, switch to a default theme, rename .htaccess. Each eliminates a category of cause.
SEARCH THE EXACT TEXT
Not a description. The literal error string, in quotes.
