WordPress FTP Error: "Unable to connect to FTP server"

I have a problem that I want to fix for two days. I searched the internet and tried to apply several suggestions from other posters.

So I have a selfhosting webserver: CentOS7, Apache, PHP, MariaDB, OpenSSH and Pure-FTPd.

I found a nice guide that combines MariaDB and Pure-FTPd. I've used vsftp before, but later I found using the database to store valid FTP users more robust and convenient.

So I successfully set up the FTP server and logged in to FileZilla from a remote client. I also managed to copy files and create a folder in the "wp-content" folder of WordPress. However, when I try to use the internal FTP solution from WordPress, I get the error message "Unable to connect to FTP server". I was able to upload plugins with: define (& # 39; FSMETHOD & # 39 ;, & # 39; directly & # 39;); Option in file wp-config.php. That worked and the plugin was successfully installed. However, I have read that this is not a safe option. I'm aware that airplane FTP is not the safe way, but I want it to work before you switch to the FTPS variant.

I also tried to paste this block into wp-config.php (essentially prefilled FTP data):
define (& # 39; FS_METHOD & # 39 ;, & text; & # 39;);
define (& # 39; FTP_BASE & # 39 ;, & # 39; / path / to / wordpress / & # 39;);
define (& # 39; FTP_CONTENT_DIR & # 39 ;, & # 39; / path / to / wordpress / wp-content / & # 39;);
define (& # 39; FTP_PLUGIN_DIR & # 39 ;, path / to / wordpress / wp-content / plugins / & # 39;);
define (& # 39; FTP_USER & # 39 ;, & # 39; username & # 39;);
define (& # 39; FTP_PASS & # 39 ;, & # 39; password & # 39;);
define (& # 39; FTP_HOST & # 39 ;, & # 39; ftp.example.org & # 39;);
define (& # 39; FTP_SSL & # 39 ;, wrong);

That did not work either.

Tl.: DR.: FTP works well with FileZilla (can connect to the server and see the wp folder), but using the WP-internal FTP solution will display an error.

I've tried all the folders that define ownership of "Apache: Apache" and myUser: myGroup (Apache, which belongs to my group).
WordPress permissions:
find / var / www / -type d -exec chmod 755 {} ;
find / var / www / -type f -exec chmod 644 {} ;

as well as
find / var / www / -type d -exec chmod 775 {} ;
find / var / www / -type f -exec chmod 664 {} ;

Nothing worked. I'm really out of ideas here.

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