Azure pipeline getting error: [error]The read operation failed, see inner exception on mac hosted agent

Question

im getting this error, which i try to find why and what happened Suddenly: and more importantly how to debug such an error . what this line means :

Error The read operation failed, see inner exception.

where is this : inner exception?

020-09-30T18:47:22.0199830Z ##[section]Starting: Initialize job
2020-09-30T18:47:22.0201330Z Agent name: 'Hosted Agent'
2020-09-30T18:47:22.0201750Z Agent machine name: 'Mac-1601490664598'
2020-09-30T18:47:22.0202040Z Current agent version: '2.175.2'
2020-09-30T18:47:22.0219900Z Current image version: '20200904.1'
2020-09-30T18:47:22.0229850Z Agent running as: 'runner'
2020-09-30T18:47:22.0293150Z Prepare build directory.
2020-09-30T18:47:22.0595770Z Set build variables.
2020-09-30T18:47:22.0631220Z Download all required tasks.
2020-09-30T18:47:22.0751440Z Downloading task: CmdLine (2.164.2)
2020-09-30T18:48:02.2372880Z Downloading task: UseRubyVersion (0.165.2)
2020-09-30T18:48:48.2651220Z Downloading task: DownloadBuildArtifacts (0.167.2)
2020-09-30T18:51:03.2405560Z ##[warning]Failed to download task 'DownloadBuildArtifacts'. Error The read operation failed, see inner exception.
2020-09-30T18:51:03.2423990Z ##[warning]Inner Exception: {ex.InnerException.Message}
2020-09-30T18:51:03.2428450Z ##[warning]Back off 23.799 seconds before retry.
2020-09-30T18:53:07.4698560Z ##[warning]Failed to download task 'DownloadBuildArtifacts'. Error The read operation failed, see inner exception.
2020-09-30T18:53:07.4701220Z ##[warning]Inner Exception: {ex.InnerException.Message}
2020-09-30T18:53:07.4704340Z ##[warning]Back off 13.329 seconds before retry.
2020-09-30T18:57:08.7191850Z ##[error]The read operation failed, see inner exception.
2020-09-30T18:57:08.7198800Z ##[section]Finishing: Initialize job

Answer 1

You are not the only one who encountered this interruption, see this post.

I reviewed our internal service telemetry log, the issue you encountered should caused by our service event. https://status.dev.azure.com/_history

There were some exception occurred on our backend start from 15:23:27 CST, which make you encountered pipeline interruption.

how to debug such an error

As normal, it's hard for users to check the inner exception if you are using hosted pool. The detailed exception messages are recorded in our backend telemetry log. You can contact our team by clicking on Report outage button mentioned below if you are blocked again in the future and would like to know the details message about it:

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Since the event has been mitigated now, I'm sure your pipelines will work fine if you re-run the pipeline now.