It sounds as though you know your username and password, but if not you can always go into PHPMyAdmin (Or whatever Db tool your server uses) and navigate to the users table. In there you can see your users, and edit your details as required, including your password which you can simply overtype with new after encrypting it in MD5 format.
If this is trying to log in and kicking you straight back to the login page it may be worth looking in your server root for a file named error_log
, this will help you identify any errors, or you can edit wp-config.php
in the site’s root setting wp_debug
to true near the end of the page. Doing this should stop the page from just redirecting you without notification and give a print out of the error, if there are, any at the top of the page.
This may not help, we could probably do with some more details from you before the community can help further. Depending on your hosting environment, it could be that your PHP version is out of date and needs updating.
Hope this helps. Ben.