451 4.7.0 Timeout waiting for client input
... / 451 4.7.0 Timeout waiting...
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Question

451 4.7.0 Timeout waiting for client input

by
NorbertK3
Created on 2023-11-28 10:07:05 (edited on 2024-09-04 14:24:34) in MX Plan

I have a problem sending messages to customers who use protected.outlook.com
Sending usually ends with the error "451 4.7.0 Timeout waiting for client input" or "timed out while sending message body"
To other mail servers messages arrive without any problems.
I tried changing MTU, setting DF, but without success