Gmail 550 5.2.1
Account inactive, or receiving too fast
Gmail 550 5.2.1 means: account inactive, or receiving too fast. It is a permanent failure, so do not retry it unchanged. If Gmail says the account is inactive, remove or suppress the address. If it says the user is receiving mail too fast, retry later.
Gmail’s exact wording
Quoted from Google Workspace Admin Help: Gmail SMTP errors and codes, checked 2026-11-05. Placeholders are Gmail’s own.
Reply text
The email account that you tried to reach is inactive. For more information, go to https://support.google.com/mail/?p=DisabledUser
Reply text
The user you are trying to contact is receiving email at a rate that prevents additional messages from being delivered. For more information, go to Limits for sending & getting email.
| Who sends it | Gmail and Google Workspace |
|---|---|
| Basic code | 550: Requested action not taken: mailbox unavailable (e.g., mailbox not found, no access, or command rejected for policy reasons) (RFC) |
| Enhanced code | 5.2.1: Mailbox disabled, not accepting messages |
| Permanent or temporary | Permanent (5xx) |
| Verifying the list prevents it | Yes, verification catches this |
In practice
Gmail uses the same code for two situations. The first, the account is inactive, comes with a link to Google's disabled-user help page and means the account has been suspended or disabled; treat it like a hard bounce. The second, receiving mail at a rate that prevents delivery, is a per-recipient limit and is the permanent counterpart of 450 4.2.1. Read which sentence your bounce contains before deciding to remove the address.
What the sender should do
If Gmail says the account is inactive, remove or suppress the address. If it says the user is receiving mail too fast, retry later.
Would verifying the list have prevented Gmail 550 5.2.1?
Yes, verification catches this
A mailbox check asks the recipient's server whether the address and domain can receive mail, without sending anything, so the address is flagged before the send instead of bouncing against your domain.
Common questions
- What does Gmail 550 5.2.1 mean?
- Gmail 550 5.2.1 means: account inactive, or receiving too fast. It is a permanent failure, so do not retry it unchanged. If Gmail says the account is inactive, remove or suppress the address. If it says the user is receiving mail too fast, retry later.
- Should I retry after Gmail 550 5.2.1?
- No. It is a permanent (5xx) failure, so the same message to the same address will fail again. Fix the cause first. If Gmail says the account is inactive, remove or suppress the address. If it says the user is receiving mail too fast, retry later.
- Would verifying my list have prevented Gmail 550 5.2.1?
- Yes, verification catches this. A mailbox check asks the recipient's server whether the address and domain can receive mail, without sending anything, so the address is flagged before the send instead of bouncing against your domain.
The same code elsewhere
Sources
- Google Workspace Admin Help: Gmail SMTP errors and codes (checked 2026-11-05)
- IANA: SMTP Enhanced Status Codes registry (checked 2026-11-05)
- RFC 5321: Simple Mail Transfer Protocol, section 4.2.3 (reply codes) (checked 2026-11-05)
Registry and provider wording is quoted exactly; guidance is written by the SimpleVerifier Team.
SimpleVerifier Team · Last checked against the sources 2026-11-05