Kann mir jemand diesen Fehler erklären?

Code:
[2022-09-14 11:01:24] app.CRITICAL: An exception occurred. {"exception":"[object] (Swift_TransportException(code: 0): 
Connection to ssl://sslout.df.eu:465 Timed Out at /kunden/320191_64569/fahrradclaus-c4-2021/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/AbstractSmtpTransport.php:404)"} []
Danke