Genmail blog · April 1, 2026
Why OTP emails feel slow
The disposable inbox is ready; the sender’s mail pipeline might not be.
OTP and verification emails can be delayed by greylisting, spam filtering, and sender-side queues, which sometimes causes short-lived disposable inboxes to expire before mail arrives.
Greylisting still exists
Some mail servers temporarily reject the first delivery attempt from unknown IPs, accepting the retry minutes later. That pattern protects against dumb spam bots but annoys humans staring at an empty inbox. It is one reason “instant” verification is not always instant.
Reputation and content filters
High-volume verification mail can look like bulk traffic. Disposable domains sometimes score differently than Gmail or Outlook. The message may sit in a queue, land in spam, or be dropped depending on the sender’s configuration—not something you can fix from the signup form.
What you can control
Trigger one resend after a reasonable wait, keep your temp inbox open, and complete the flow in one sitting. If delays are chronic for a specific vendor, a longer-lived inbox or a mainstream address may be the pragmatic fix.
Read next
On the blog
Guides & use cases
- 10 Min Mail expired — 10 Min Mail expired before your code showed up?
- Temp mail blocked — Temp mail blocked or not receiving mail