Cannot publish or schedule posts

I just made an Instagram story that I wanted to post via the Express app. When I click on "Share" and select the specific platform, then fill out the important details, the "Publish" button is grey and is unclickable. It does not change no matter what I do. Also, despite the "preview" working with the Instagram Post category, it keeps loading when it's selected to "Story".

I can download the file just fine, but it would have made it much easier for me to publish it via the app as I am a blind Adobe user and would make it more accessible that way.

My Instagram account is linked, so it should work fine otherwise.

Thank you in advance!