S
Supabase2w ago
seb1

OTP emails not working with Resend SMTP, is working fine with built-in Supabase SMTP

I just went through the Resend walkthrough to create an SMTP server with the supabase integration. Everything looks good and SMTP settings on supabase dashboard align with what I am seeing on Resend. When I try to send an OTP email, there is a 500 in my Auth logs and the only info I get is
"msg": "500: Error sending magic link email",
"error": "gomail: could not send email 1: short response: 450",
"msg": "500: Error sending magic link email",
"error": "gomail: could not send email 1: short response: 450",
There are no logs at all in my Resend dashboard so my intuition is that the error is being thrown somewhere in Supabase. To isolate the issue I turned off the "Enable Custom SMTP" and everything worked fine again. Any advice would be greatly appreciated.
6 Replies
garyaustin
garyaustin2w ago
Check the auth log and see if there is any error info. Probably some sort of credential thing.
seb1
seb1OP2w ago
This is the whole message, can't find anything helpful:
{

"error": "gomail: could not send email 1: short response: 450",
}
],
"timestamp": 1755114194000000
}
{

"error": "gomail: could not send email 1: short response: 450",
}
],
"timestamp": 1755114194000000
}
garyaustin
garyaustin2w ago
No, not much help. I believe that means it can't connect to the Resend server or Resend is getting an error. But as you say you checked the Resend logs, seems like connection.
seb1
seb1OP2w ago
F, I'm going to redo this whole thing top to bottom and report back It was a subdomain thing, sorry to bother
Fabrizio
Fabrizio2w ago
I'm also having the same issue, supabase not sending emails, but in both ways, supabase built in and via resend...
garyaustin
garyaustin2w ago
Not likely related. Please ask in a new topic and include any auth log errors and changes to templates.

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