"Error 401 Failed to authenticate." when attempting to send data to an HTTP source endpoint

Problem:

Our HTTP collectors are returning the following 401 error response. When will our service resume as expected?

Error 401 Failed to authenticate.

Cause:

There are two primary causes of a 401 error when posting to a Sumo Logic HTTP Source endpoint. 

1.) The URL token is not currently valid. This may happen when:

• When the URL supplied is not complete or is missing the full token path. 
• A new URL has been generated for an existing HTTP Source. In this case, the new URL may take up to 5 minutes to propagate across the Sumo Logic receiver services. During this period of time, the old URL may continue to work but the new URL will fail. Once the new URL takes effect the old URL will begin to fail and the new URL will then respond correctly. 

2.) When using a Sumo Logic Free account where you have hit your ingest limits and Collection has been disabled. During the period of time where the collection is disabled, Sumo Logic will return a 401 response on any requests to your HTTP Source endpoint. 

Resolution:

1.) Make sure the endpoint supplied is a valid HTTP Source URL. You can confirm your URL by going to  "Manage Data -> Collection tab" and next to your HTTP Source opening the "Show URL" link.

• To verify your endpoint is valid you can perform a cURL request to push a sample message to your source endpoint and verify the response is a 200 success.

curl -v -X POST -d "Test data" "<the_source_url>"

• After requesting a new URL on your HTTP source, allow at least 5 minutes for the Sumo Logic receiver caches to clear before POST'ing to the new HTTP endpoint. 

2.) When this issue is seen within a Sumo Logic Free account with disabled collection you will need to wait until your ingest and storage limits have gone back below the limits of this account type. Once your account is able to accept new data you should no longer see a 401 response on your requests. For more information on Free account limits please see the Important notes on Sumo Logic Free accounts documentation.