I have a problem with my hosting. Locally everything works fine. I cloned my website(typo3 12.4.9), installed composer, imported the database and adjusted the php version to the version of the hosting company. Now I can access my domain in the browser, but get a 503 error in the Typo3 backend. In the frontend I get the following error: 404 Page Not Found The page did not exist or was inaccessible. Reason: No site configuration found.
If you require further informations please ask. Thanks in advance.
Edit: Added the missing db data to the settings.php and added .htaccess in the public directory (https://docs.typo3.org/p/lochmueller/staticfilecache/main/en-us/Configuration/Htaccess.html). Now I get the backend login but I doesnt work and redirects me to "page not found" after submit. The frontend error is still there. Login via /typo3/install.php still shows the 503 error.
You linked https://docs.typo3.org/p/lochmueller/staticfilecache/main/en-us/Configuration/Htaccess.html which only contains ext:staticfilecache related htaccess rules.
First, you should use the shipped htaccess for the used TYPO3 coreversion in use, for example following for 12.4.9: https://github.com/TYPO3/typo3/blob/v12.4.9/typo3/sysext/install/Resources/Private/FolderStructureTemplateFiles/root-htaccess
If you are using the ext:staticfilecache add the mentioned rules in the documentation to the beginning of the TYPO3 core htaccess file - at least before mentioned lines.
# If you use the oldschool .htaccess rewrite rules that come with
# the TYPO3 dummy, then the relevant StaticFileCache configuration
# should be inserted in the .htaccess file just before these lines:
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-l
RewriteRule .* index.php [L]