@Bunnz said in "proxy handshake error"/"Failure when receiving data from the peer" when using proxy with Mail Module:
And proxy is working in HTTP request just fine
email ports are disallowed for these proxies.
ReCaptcha module is enabled, it can reduce browser authenticity.
So it is recommended to turn it off, unless you are working with recaptcha.

Should I take this warning seriously?
If you need to solve a captcha, then you use the module. If you don't need to solve a captcha, then you don't use it)
There is no specific answer to your question, it all depends on the site you work with.