I’ve got a couple domains I selfhost and I used Spectrum’s mail.twc.com smtp server for my smarthost. I few weeks ago I noticed I couldn’t send mail to my gmail using my domains and never received a bounce back with the error. Today I started getting a error finally, but it looks like I can’t send out anything that doesn’t match my spectrum email. Trying to figure out my best course of action that is free. I only send around 200 emails/month across all my domains. I’ve got a oracle free tier but this might be against their TOS. It seems my options are resend or sendgrid free tiers?
Action: failed
Status: 5.1.0
Remote-MTA: dns; mail.twc.com
Diagnostic-Code: smtp; 550 5.1.0 sender rejected. The
email address you are sending as must match the email address you used to
auth. Please check your SMTP settings. AUP#Out-1500
Many suggest Amazon SES as it is dead ass cheap. Free tier SMPT relay services often add advertising lines or other shenanigans to mails. I use mailjet but it is quiete expensive. I send under 10k mails per month but sadly most SMPT services do not have small/mid tiers.