There are several potential causes for a WordPress login page that refreshes or redirects after attempting to log in.
Here are some possible solutions you can try:
Check your WordPress version: If you are using an outdated version of WordPress, it is possible that there is a known issue with the login system. Updating to the latest version may fix the problem.
Check your plugins: If you have recently installed a new plugin or activated a plugin that you previously had deactivated, it is possible that the plugin is causing the login issue. Try deactivating all of your plugins and then reactivating them one by one to see if the issue persists.
Check your theme: Similar to plugins, if you have recently changed your theme or activated a new theme, it is possible that the theme is causing the login issue. Try switching to a different theme to see if the issue persists.
Check your browser: If you are using an outdated or unsupported browser, it is possible that the login issue is due to browser compatibility issues. Try using a different browser or updating your current browser to the latest version.
Check your .htaccess file: If your .htaccess file has been modified or is causing problems, it can affect the login process. Try renaming your .htaccess file to something else (e.g. .htaccess_old) and then logging in again. If this fixes the issue, you can then troubleshoot the .htaccess file to determine the cause of the problem.
Check for conflicting JavaScript: If your WordPress site is using custom JavaScript, it is possible that the JavaScript is conflicting with the login process. Try deactivating any custom JavaScript to see if the issue persists.
Check your database: If none of the above solutions work, it is possible that there is an issue with your WordPress database. Try repairing your database using a plugin like WP-DB Manager or using the wp-cli command-line tool.
If none of these solutions work, you may need to seek further assistance from a WordPress developer or from the WordPress support forum.