Why does my git repo throw errors when pushing to deployment server?

Why does my git repo throw errors when pushing to deployment server?

I recently set a a repo up on Beanstalk app to deploy my app.
I have a repo and a submodule in it with the following settings.
In .git/config I have:
[submodule "vendor/php-instagram-api/php-instagram-api"]
path = vendor/php-instagram-api/php-instagram-api
url = git@made-by-mark.beanstalkapp.com:/made-by-mark/everydayfolk.git
In my .git/.gitmodules I have:
[submodule "phpinstagram"]
path = vendor/php-instagram-api/php-instagram-api
url = git@made-by-mark.beanstalkapp.com:/made-by-mark/everydayfolk.git
Is there a conflict here? When I commit I get no errors but when I do git
push beanstalk master in the beanstalk deployment area I get an error
saying:
Warning: Permanently added 'made-by-mark.beanstalkapp.com,50.31.156.71'
(RSA) to the list of known hosts. fatal: reference is not a tree:
fc4d8cf4f05c51e71ddbc7d7b80f639c68b39405 Unable to checkout
'fc4d8cf4f05c51e71ddbc7d7b80f639c68b39405' in submodule path
'vendor/php-instagram-api/php-instagram-api'
I have tried many fixes but things just aren't getting anywhere. Can
anyone see what the issue may be?
Cheers