Amplify build error "Could not read from remote repository"

I'm trying to setup a Vue app in Amplify Console, but getting a build error.

The app is hosted in a private Bitbucket repository and has dependencies on other private Bitbucket repsoitories (owned by same account) that are referenced in the package.json file, like so:

"foo": "git+ssh://git@bitbucket.org:example/foo.git#v1.0.0"

During the build I get the following kind of error:

error Command failed.
Exit code: 128
Command: git
Arguments: ls-remote --tags --heads git@bitbucket.org:example/foo.git
Directory: /codebuild/output/src238132917/src/bar
Output:
Warning: Permanently added the RSA host key for IP address '18.205.93.2' to the list of known hosts.
Permission denied (publickey).
fatal: Could not read from remote repository.
Please make sure you have the correct access rights
and the repository exists.

After connecting Amplify to Bitbucket, I noticed an SSH key is added to the repository I connected, so I added the same key to the other repositories that are dependencies, but the build still fails.

Is it possible to make the build work?