Reproduction steps:
1. Create a new project
2. Extract and import contents of "Editor.zip" into your project
3. Enable Cloud Diagnostics for the project (read note 1)
4. Close the Editor completely
5. Build the project using Command Line Argument (IMPORTANT to read note 1):
<UNITY EDITOR PATH> -batchmode -buildTarget iOS -runTests -testplatform playmode -projectpath <PROJECT PATH> -executeMethod CliBuild.MakeiOS -username <LOGIN/E-MAIL> -password <PASSWORD> -quit
6. After the build completes, open the Xcode project located in "build" folder (at the root of the project)
7. Try deploying the project to a device

Expected result: the project successfully deploys or you will have received an error in step 5 indicating that you need to use another account
Actual result: Xcode throws an error message "Please provide an auth token with USYM_UPLOAD_AUTH_TOKEN environment variable", when building in step 5 no indication of something being wrong appears (read note 2)

Reproducible with: 2018.4.26f1, 2019.3.0a1, 2020.2.0a19

Notes:
1. In step 5 you need to use a different account than the one you used for enabling Unity Services/ Cloud Diagnostics for the project
2. The error message in Xcode is not very informative for the customer (it is possible to make out from keywords such as auth_token, but it should've thrown an error in the building process that more clearly described the problem)
3. This looks similar to Case 1167025 (the difference is that it was not written there that you need a different account)