The cause for an error when using port 465 for an encrypted version of SMTP is interesting. The IANA was responsible for assigning this port to support an encrypted version of SMTP. However, this port assignment did not last, and now this port is available for another application. Due to this change, most email service providers do not support port 465 for SMTP; therefore, connections made via this port will fail.
You can use port 587 when using SMTP with encryption to avoid this issue. However, it is essential to note that port 587 is not the reserved port when using SMTP with encryption.
View all errors