We'd like to help. Have you tried following the steps in our Help Center article to add credits to your video: https://goo.gl/5nivFn ? Let us know.
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You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more
Can you let us know if you see an error message while trying to add credits? Keep us posted.