What does "Error message mail transport server 452-452 4.1.1 temporary failure" mean?

[clanpark]

I am trying to send a simple 5 paragraph text email (no attachments) to 66 receipients.  Everytime I try to send the email I get the message, "Message can not be send.  Error message mail transport server 452-452 4.1.1 temporary failure."  I spent 40 minutes on the phone with a technicialn from advanced technical support.  He could not tell me what the error message meant nor could he fix the problem.  Any ideas out there?

[Again]

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@clanpark wrote:

I am trying to send a simple 5 paragraph text email (no attachments) to 66 receipients.  Everytime I try to send the email I get the message, "Message can not be send.  Error message mail transport server 452-452 4.1.1 temporary failure."  I spent 40 minutes on the phone with a technicialn from advanced technical support.  He could not tell me what the error message meant nor could he fix the problem.  Any ideas out there?

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One or more of the email addresses you are sending to have a problem.  Check the addresses to make sure they are correct.

[clanpark]

Shouldn't the system highlight which email address is the problem?

[BruceW · Accepted solution]

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@clanpark wrote: ... 452-452 4.1.1 temporary failure ...

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https://postmaster.comcast.net/smtp-error-codes.php#452 says:

452 - [Too many emails sent on this session]	Comcast allows 1000 emails per session. This error results when that limit is exceeded.
452 - [Too many recipients for message]	Comcast allows 100 recipients per message. This error results when that limit is exceeded.

[clanpark]

I went one by one through the 66 email receipients and found the one bad email address.  Removed it and the message went through fine.  The bad email appears to be a legitimate address, so I don't know what the problem is with it.  In the past I would get notifications from the system saying mail was undeliverable to a particular address.  I never received any such notification with this email.  Sad how the advanced tech support agent I spoke with on the phone had no idea what the problem was or how to fix it.