DKIM record not being verified by Resend

Question

I will be honest and DNS settings are somewhat a weak point of mine so please forgive me any ignorance/stupidity on my part.

I have a domain that is currently sending transactional emails via Mailersend and I am looking to migrate to Resend, ideally with both in place at first but once I test Resend is working remove Mailersend.

My site is hosted on Vercel and the domain is registered through Fasthosts. I initially put the three DNS records in Fasthosts and then realised it should be Vercel, so I removed them from FH and added them to Vercel. It eventually verified two of them, but the DKIM isn't verifying. Thinking it might be I need it on FH (I struggle to understand what should go where so tends to be trial and error) but that still isn't working.

However its been a few days and that isn't working and I think it should be in Vercel anyway. The existing DKIM record is in Vercel and has a different name so I don't think its conflicting, but I can't figure out why the DKIM record is the only one that can't be verified.

Using tools (including easydmarc which Resends recommends) the value seems to be okay, but the verification isn't working and its been a few days now.

I doubt its this but the only difference I can see between what Resend recommends and what I've done is they suggest TTL should be auto and as Vercel doesn't allow that I've chosen 60 but other than that it is exactly the same.

Any recommendations on what I should be looking out for would be much appreciated.

Answer 1

If you have an existing spf record (usually when you have outlook set up or any other email provider) you need to combine both spf records.

In my case, I had outlook configured in my dns records and adding another TXT spf record didn't work until I merged them using this tool which I found after finding this video two days later which solved the error.

I was getting a: "We can't verify that this email came from the sender so it might not be safe to respond to it." error message.

Answer 2

I have been needing to do the same thing. I had an old Next.js application on Next 11 with Nodemailer and Node/Express, this setup no longer worked with Next14 so I wanted to migrate to Resend using Route Handlers to send Emails. I have spent my morning with the same issue. I ended up deleting the domain a few times but added the records and DKIM record like this in my registrar

MX send.yourdomain.com

TXT send.yourdomain.com

TXT resend._domainkey.yourdomain.com

The first two records verified quickly and the DKIM in about 12-15 minutes.

I have not tested email sending yet, but my domain is at least verified!

I hope it helps.