The recipient mailbox exists but has been disabled, suspended, or is not currently accepting messages. This can be a permanent or temporary condition depending on whether the account is suspended or permanently deactivated.
What Does Error 5.2.1 Mean?
Enhanced status code 5.2.1 indicates the recipient mailbox exists in the system but is not currently accepting messages. The account may be disabled by an administrator, suspended due to inactivity, or temporarily locked for security reasons.
Some organizations disable mailboxes when employees go on extended leave and re-enable them later. However, if the account was permanently deactivated, this bounce is permanent. After 2-3 bounces with this code, suppress the address. If the account is reactivated, the recipient should re-subscribe.
Common Causes
- Account has been suspended or deactivated by an administrator
- Mailbox disabled due to prolonged inactivity
- Account locked for security reasons (compromised account)
- Mailbox in a transitional state during migration
- User exceeded storage quota and account was suspended
How to Fix Error 5.2.1
- Suppress the address after 2-3 consecutive bounces with this code
- If the recipient is known, contact them through another channel
- Do not keep retrying - treat as a hard bounce for list hygiene
Frequently Asked Questions
Bounce code 550 5.2.1 means the recipient's email account exists but has been disabled or suspended and is not accepting messages. Gmail returns this as "The email account that you tried to reach is disabled." The account may have been deactivated due to inactivity, policy violations, non-payment (for business accounts), or security concerns. This is a permanent failure and should be treated as a hard bounce.
Email accounts are typically disabled by the mail provider for several reasons: prolonged inactivity (Gmail and Yahoo may disable accounts after extended periods of no login), violation of terms of service, security breaches or suspected compromise, exceeding receiving rate limits, or administrative action by a company's IT department (such as when an employee leaves). The sender cannot re-enable the account -- only the account owner or their administrator can restore it.
Yes. Error 5.1.1 means the mailbox does not exist at all -- the address is completely invalid. Error 5.2.1 means the mailbox exists in the system but has been disabled and is not accepting mail. Both are hard bounces requiring suppression, but the distinction matters for list hygiene: a 5.1.1 address should be permanently removed, while a 5.2.1 address could theoretically be re-enabled by the owner in the future, though you should not count on it.
Yes, treat 5.2.1 as a hard bounce and immediately suppress the address. Continuing to send to disabled accounts increases your bounce rate and damages your sender reputation with Gmail, Microsoft 365, and Yahoo. While there is a small chance the account owner may re-enable their mailbox, re-enabling is unpredictable and may never happen. If the recipient re-engages through another channel, you can verify the address is active before adding it back.