PHP Warning: ftp_login(): SSL/TLS handshake failed in /home/client/libraries/php-ftp-client/FtpClient/FtpWrapper.php on line 85 PHP Warning: ftp_login(): AUTH TLS successful in /home/client/libraries/php-ftp-client/FtpClient/FtpWrapper.php on line 85
Happend when a PHP client programm was trying to upload pdf files to ProFtpd server with lower OpenSSL version (Debian 10 → Debian 9).
Solved by upgrading the server with ProFtpd to Debian 10.