Troubleshooting
Common issues and how to resolve them.
Emails not sending
If an API call returns an error or emails never arrive, work through this checklist:
API key is valid and not revoked
Go to Dashboard → Developer and confirm the key is listed and not revoked. If you've lost the key, revoke it and create a new one — keys are shown only once.
The sender address exists as a mailbox
The from address must be a real mailbox on the domain the API key is scoped to. You cannot send from random@example.com unless that mailbox exists. Check Dashboard → Mailboxes.
Domain is verified and active
An unverified domain cannot send email. The domain status must be Active in Dashboard → Domains.
API key is scoped to the correct domain
Each API key is tied to exactly one domain. If the from address is on a different domain than the key's domain, the request will be rejected with a 403.
scheduledAt is not in the past
If you passed a scheduledAt value, make sure it is a future Unix millisecond timestamp. A value in the past will return a validation error.
Either html or text is provided
The send endpoint requires at least one of html or text in the request body. Sending an empty body will return 400.
Domain verification issues
DNS record not found
After adding a TXT record, use a DNS lookup tool (e.g. dig TXT yourdomain.com or MXToolbox) to confirm the record is visible. If it isn't, double-check you saved the record at your DNS provider.
Record added to the wrong subdomain
The verification TXT record should be added to the root domain (@), not to a subdomain unless RemindMe specifically instructs otherwise.
Multiple conflicting SPF records
A domain can only have one SPF TXT record. If you have two records starting with v=spf1, merge them into one. For example:v=spf1 include:amazonses.com include:other-provider.com ~all
TTL caching delay
DNS records are cached by your TTL (time-to-live) value. If you recently added or changed a record, wait for the TTL to expire before re-verifying. A common TTL is 3600 seconds (1 hour).
Domain registrar propagation
Some registrars take longer to propagate changes. If dig shows the record but RemindMe still shows unverified, click Verify now again — RemindMe re-checks on demand.
Bounces & rejections
A hard bounce means the recipient address does not exist or the server permanently rejected the email. A soft bounce is a temporary failure (mailbox full, server temporarily unavailable).
Check the recipient address
The most common cause of bounces is a typo in the recipient address. Double-check the to field.
Your domain is not warmed up
New domains and IP addresses need to be "warmed up" — start with small send volumes and gradually increase over days. Sending a large blast from a brand-new domain will trigger spam filters and rejections.
SPF or DKIM is not configured
Receiving servers check SPF and DKIM before accepting email. If either is missing or misconfigured, mail may be silently rejected or sent to spam. Verify your DNS setup in Domain Setup → SPF & DKIM.
Recipient marked you as spam
If a recipient previously marked email from your domain as spam, their provider may automatically reject future sends. Remove unengaged recipients from your lists regularly.
Content triggers spam filters
Avoid excessive caps, suspicious links, or spam trigger words in subject lines and body content. Test your email content with a spam-checking tool (e.g. Mail-Tester) before sending to a large list.