H5P Libraries Installation Failure

We have an instructor whose Pressbooks instance won’t install H5P libraries properly. When on the H5P builder under “Add New” we click “Get” on a particular H5P type, then “Install”, it will run and say “[H5P type] successfully installed!” and state how many new libraries were added. If we then click “Use” from there, it says “Loading, please wait…” but never successfully loads anything.

When we click over to Libraries under H5P Content, the libraries which were supposedly just installed do not appear in the list. The only installed library shown is “Font Awesome (4.5.4)” despite us having run through the above process several times for several H5P task types.

The plugin is activated and updated, but for some reason it can never actually install any libraries, and thus no H5P tasks can be created or uploaded.

We discovered this issue because the instructor has a large set of H5P tasks built elsewhere that she wants to move into a Pressbook. When we attempt to upload a .h5p file through the builder under Add New, it similarly shows a success statement, but then the task is nowhere to be found in All H5P Content.

I have only encountered this issue on one Pressbooks instance. I have compared various settings to other instances where H5P is working just fine and I can not find any reason why it should not be working just like the others. Any ideas where I should look to find a solution, or how to further troubleshoot the issue? Or is there some chance that this instance has a corruption somewhere and we should just create a new one?