how to fix 550 5.5.0 Requested action not taken: mailbox unavailable (S2017062302). [CY6PEPF0000004E.namprd03.prod.outlook.com 2026-10-09T02:18:47.682Z 08DF2566499EFB73] error with gmail and outlook interaction.

Question

how to fix 550 5.5.0 Requested action not taken: mailbox unavailable (S2017062302). [CY6PEPF0000004E.namprd03.prod.outlook.com 2026-10-09T02:18:47.682Z 08DF2566499EFB73] error with gmail and outlook interaction.

Vance Bridgers 0

Address not found

Your message wasn't delivered to vancebridg***@outlook.com because the address couldn't be found, or is unable to receive mail.
The response from the remote server was:

550 5.5.0 Requested action not taken: mailbox unavailable (S2017062302). [CY6PEPF0000004E.namprd03.prod.outlook.com 2026-10-09T02:18:47.682Z 08DF2566499EFB73]

0 comments

1 answer

Your answer

Answer 1

Francisco Montilla 31,090 Independent Advisor

Hello,

That 550 5.5.0 S2017062302 error means Microsoft servers simply cannot find the address you are trying to send your message to.

There are usually only a few reasons this bounce back happens. The most common is a simple typo in the first half of the email address right before the at symbol. The second is that the recipient mailbox was actually deleted due to inactivity over the years, or it might be experiencing a suspension or temporary service-related problem on their end.

Are you typing this address manually from memory, or are you replying directly to a message they recently sent you?

Let me know so we can try to figure out the context here.

Vance Bridgers 0 Reputation points

2026-10-09T18:49:50.62+00:00

I was typing the address manually since gmails aren’t receiving any emails from the outlook account. There is no typo in the outlook address and the outlook account was made yesterday. It is showing as correctly verified and no account issues. This error occurred when a Gmail address attempted to email the outlook account. My new outlook is only receiving mail from other outlook accounts and shows emails to Gmail accounts as sent but the Gmail accounts never receive the messages. I checked and have no rules or junk mail restrictions set and even attempted to add specific gmails as safe senders.
Francisco Montilla 31,090 Reputation points Independent Advisor

2026-10-10T01:11:32.61+00:00

When an account is only a day old, this error usually comes down to Microsoft's external edge servers taking up to 24 to 48 hours to sync the new address for outside senders like Gmail.

To help narrow this down, did you create this as a completely fresh Microsoft account from scratch, or did you add this address as an alias onto an existing account?
Vance Bridgers 0 Reputation points

2026-10-10T16:32:47.7633333+00:00

It is completely new as a Microsoft and outlook account and is listed as primary instead of alias. I probably have to wait for that sync like you said! Thank you so much for offering the help and insights.
Francisco Montilla 31,090 Reputation points Independent Advisor

2026-10-11T02:25:33.6566667+00:00

Glad that helped clear things up! Give it until tomorrow and shoot another quick test email from Gmail to check. If it is still bouncing after a couple of days, just reply back here and we can take another look.