[fix] DKIM verification incorrectly succeeds with multiple TXT lines

[mtrimpe]

Describe the bug

Node.js version:

OS version:

Description: When setting up DKIM key I accidentally left a second line of the DKIM key (from a failed attempt at using 255+ character key) in my DNS records. The verification UI showed me that I had set everything up correctly... but all sent emails were of course being rejected by downstream mail servers.

Actual behavior

DKIM verification succeeds if one of multiple available TXT record lines matches the required value.

Expected behavior

DKIM fails if multiple TXT record lines are available while only a single record should be used.

Code to reproduce

Checklist

• I have contacted support and they told me to raise an issue here.