Question : 557 sorry, too many recipients (#5.7.1) error when sending to groups in Lotus Notes

I have a Lotus Notes client who is trying to send email to a group of 150 individuals.  After sending she gets a delivery failure report that says this:
557 sorry, too many recipients (#5.7.1)
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You can resend the undeliverable document to the recipients listed above by choosing the Resend button or the Resend command on the Actions menu.  
Once you have resent the document you may delete this Delivery Failure Report.
If resending the document is not successful you will receive a new failure report.
Unless you receive other Delivery Failure Reports, the document was successfully delivered to all other recipients.
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All the email addresses are in a single group consisting of around 150 addresses.
Do you think there a limit on the group size in Domino or on the client itself?
Thanks in advance.

Answer : 557 sorry, too many recipients (#5.7.1) error when sending to groups in Lotus Notes

it is probably  
553 sorry, too many recipients (#5.7.1)
(as 553 is the code for too many recipients and #5.7.1 is delivery refused)
I agree with sjef, the error is coming from ISP or recipient side that limited number recipients per message. split the group into smaller chunks