You browse a queue and get a response "Queue does not have any messages" or only some of the messages are shown.
Click on the Browse Options icon on the viewlet tool bar to see the settings. You may have a Message Criteria browse option set that is causing all or some of messages to be skipped, for example, a Message Descriptor (MD) property Put Date with a year 2020 that you left from an earlier browse, and the messages on queue have a Put Date of 2021. That would block all of them from being browsed. Or the MD Message Format might be set to MQSTR (string) and the queued messages have a different format.
Either change some or all of the MD search criteria or delete the Message Criteria option and try the browse again.