First, I added the submodule to github as public repo, then I added the submodule to odoo.sh db, it worked fine. Then I change the repo to private, and I added it to odoo.sh settings/private repos and copied the deploy keys to the submodule deploy keys in github, I cloned the main repo of the project, updated the remote submodule and then add, commit and push, it started to update but failed!
Your help is highly appreciated.
thanks