Some users notice that forwarded mail can take minutes or hours to appear in their inbox, even though the addy.io dashboard already shows the alias as having forwarded the message. Delivery is often instant at other times. This article explains why that happens and what you can do.

Why the dashboard can show "forwarded" before it is delivered

When an email reaches your alias, addy.io accepts it, processes it, and attempts to deliver it to your recipient address (for example @gmail.com).

The dashboard counts a forward once addy.io has completed its delivery attempt to your email provider's mail servers. If they accept the message into their queue, or return a temporary response asking the sending server to try again later, addy.io has already done its part. Your email provider may still hold the message internally before it appears in your inbox.

So "forwarded" on addy.io does not always mean "already in your recipient inbox" - it means the message was handed off for delivery to them.

Gmail temporary rate limits (421 4.7.28)

A common cause of long delays is a temporary rate limit from Gmail. In mail server logs this often appears as status deferred with an error similar to:

421 4.7.28 Gmail has detected an unusual rate of mail originating from your SPF domain [...]. Mail sent from your domain has been temporarily rate limited.

The SPF domain in that message is usually your addy.io username subdomain (for example johndoe.anonaddy.com), not your personal @gmail.com address. Gmail is limiting how much mail it will accept in a short period from that sending domain. This is a temporary restriction (response code 421), not a permanent rejection.

addy.io's servers retry deferred messages automatically. Gmail typically accepts them once the rate limit eases, which is why some forwards arrive hours later while others are instant when volume is lower.

This is different from a failed delivery where forwarding ultimately bounces and is recorded on your Failed Deliveries page. A deferred message may never appear there if delivery eventually succeeds.

Google documents this type of limit here: Bulk Email Senders Guidelines / Unsolicited rate limit.

Why Gmail does this

Gmail applies rate limits to protect users from spam. Forwarding services send many messages from shared infrastructure and authenticated domains such as username.anonaddy.com, which can look like bulk mail to automated filters even when each message is legitimate.

Delays are more likely when:

• A large number of messages are forwarded to the same Gmail inbox in a short time
• Many different senders forward to the same Gmail account via aliases
• Gmail has recently flagged similar mail as unwanted

This is usually not caused by a misconfiguration on your Gmail account alone.

What you can do

• Wait - Temporary limits often clear on their own; retries usually succeed without any action from you.
• Check spam - Delayed mail can still land in Spam when it arrives. Mark legitimate forwards as Not spam so Gmail learns they are wanted.
• Add trusted senders - Add no-reply@addy.io and important alias addresses to your Google Contacts or safe senders where possible.
• Reduce sudden bursts - If you forward very high volumes to one Gmail inbox, spreading traffic or using another verified recipient can help.
• Adjust forwarding settings - Steps that can help Gmail accept forwards more reliably (banner, From format, encryption) are in How can I prevent or reduce failed deliveries? and the FAQ.

If mail never arrives and you see a failed delivery in the dashboard, use Downloading and viewing a failed delivery to read the exact error from Gmail.

When to contact support

Contact addy.io support if:

• Delays persist for more than 24 hours on multiple messages
• Gmail eventually returns a permanent bounce (5xx) and a failed delivery is recorded
• Only your account is affected and you have already tried the steps above

Include the approximate time the message was sent to your alias and your Gmail recipient address so the delivery logs can be checked.