Text editor issues

I have been building a website from a theme for a client, and I ran into a problem today of the text editor not working for posts and pages. I’m not sure when this occurred, but it has been a recent change.

Specifically, I can edit text and layout in the Visual editor, but the Text tab will not switch to the HTML view. Also, all but the “Link” button works. I can turn hyperlinks into regular text, but I cannot turn text into a hyperlink.

I’m assuming that it has to do with my theme because the functions are fixed when I switch to the default WordPress theme.

Any help would be very much appreciated!