It is a generic error and can occur due to several reasons.
Since the error is language agnostic, the best option is to focus on the SMTP configurations rather than syntactical errors.
Therefore, ensure that your SMTP credentials are valid by cross-checking the SMTP server guidelines. Most importantly, make sure that you are connecting using the correct port. For example, specific SMTP servers do not accept connections on port 465 but only on port 587 (hence, use TLS to connect).
Furthermore, ensure that the sender account has SMTP authentication enabled, and if none of this resolves your error, try disabling the firewall or anti-virus guard.
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