How can I make AnsPress accessible to blind people using screen readers?

I have got AnsPress installed on my website and we are using it as a platform for people to ask a team of young disabled people I’m working with how to make their organisations more accessible for disabled people. One of the young disabled people I am working with and uses a screen reader. Most of AnsPress is recognised by her screen reader but when she navigates over a text box, in order to reply to a question, she is unable to select the option to write in the text box.

Any ideas?