## The problem
Issue Azure/azure-sdk-for-python#38717 (closed, 34 comments): - **Package Name**: azure-servicebus - **Package Version**: 7.13.0 - **Operating System**: Windows 11 Pro and Linux as well (tested on both OS) - **Python Version**: 3.12.7 **Describe the bug** I get an error when I try to peek messages on some of my Azure service bus queues. It works well with other queues but fails with some (I have same permissions to both). The only difference between the queues is that the one which fails has two additional custom properties and a bigger body (131B vs 921 B).

## What to do
A bug in azure-servicebus 7.13.0 made receiver.peek_messages() fail on queues with extra custom properties or larger message bodies while working fine on other queues. The fix shipped in a newer release (maintainer confirmed the fixed version is on pypi). Fix: upgrade azure-servicebus past 7.13.0. If peek fails on some queues but not others with the same permissions, a version upgrade is the first thing to try.