Site went blank

After having installed a new team

You may want to provide us volunteers more information than that. 😉

White blank pages usually means PHP is tossing 500 errors. Check your server’s error_log file, that will usually tell you where the problem is.

If you added something such as a plugin or new theme, you can use FTP or whatever file management tools your host has provided you to simply locate that new plugin or theme directory and delete it (just that new directory and nothing else). Fixing it that way does not require being able to log into WordPress.