When attempting to run a deployment, you may run into the following error during the build step, when we try to checkout your repository at the end revision:

```
Checking out working copy of your repository at 
123abc (master)

An error occurred

Warning: Permanently added 'bitbucket.org,2406:da00:ff00::22cd:e0db' 
(RSA) to the list of known hosts. repository does not 
exist. fatal: Could not read from remote repository. 
Please make sure you have the correct access rights 
and the repository exists. fatal: run_command returned 
non-zero status for submodule/path.
```

This specifically happens when trying to fetch code from the source repository referenced in a submodule. If the source repository has changed in any way, such as being renamed, the above error will occur.

You'll need to check your `.gitmodules` file to ensure the repository URL is correct, and if necessary change it, then push the commit to your repository.