Can't send email with Namecheap

[omfg]

@snatri

5. I also tried ports 465, 587 and 25 with both TLS on and off (rebuilt it with every test)

Don’t try miscellaneous settings. Use the correct settings required by your email service provider.
https://www.namecheap.com/support/knowledgebase/article.aspx/1179/2175/general-configuration-for-mail-clients-and-mobile-devices