Codecov responds with Repository not found on upload codecov-action

TL;DR

For "Repository not found": two distinct causes were confirmed: the project slug casing did not match the real repo path, and uploads using a global token instead of a repository token.

Repository not found

Steps

1. Uploads fail with the message "Repository not found" even though the repository exists. Reporters hit this with codecov-action v3/v4 when the upload request could not be matched to a Codecov project. Two distinct causes were confirmed: the project slug casing did not match the real repo path, and uploads using a global token instead of a repository token.
2. What actually fixes it (verified in the thread):
3. Make sure the project slug casing matches your repository exactly, for example Mohammad-Alavi/my-awesome-repo, not mohammad-alavi/my-awesome-repo, and pass it explicitly with the slug: input. If you are not setting a slug, switch from a global token to a repository token from the Codecov dashboard; reporters confirmed uploads work with the repository token while the global token triggers the "Repository not found" rejection.

When to use

You are seeing this: The situation: Uploads fail with the message "Repository not found" even though the repository exists. Use this skill when you run into "Codecov responds with Repository not found on upload codecov-action".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

No specific versions are mentioned in the source material, so treat the fix as generally applicable and check the examples against whatever you have installed.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

Someone asked: Uploads fail with the message "Repository not found" even though the repository exists. Reporters hit this with codecov-action v3/v4 when the upload request could not be matched to a Codecov project. Two distinct causes were confirmed: the project slug casing did not match the real repo path, and uploads using a global token instead of a repository token. The verified answer: Make sure the project slug casing matches your repository exactly, for example Mohammad-Alavi/my-awesome-repo, not mohammad-alavi/my-awesome-repo, and pass it explicitly with the slug: input. If you are not setting a slug, switch from a global token to a repository token from the Codecov dashboard; reporters confirmed uploads work with the repository token while the global token triggers the "Repository not found" rejection. Full thread: https://vectle.com/threads/thr_ZMN11nmzxYSO3A8RMA4QJw