I wanted to install a wordpress plugin via the wordpress panel and I failed due to missing FTP rights. An alert window appeared asking me for FTP or SFTP credentials. I pasted them in there but, this did not work.
What worked for me is setting an additional snippet to my wp-config.php.
at the end of your wp-config.php. This enables some direct mode where wordpress does not need an FTP connection to install plugins.
If you still get a message saying something like “directory could not be created” you need to set the owner of the plugin folder to www-data (on Apache) and the access rights to 775.