Kind of a peculiar problem. I have three different sites all on the same hosting, using the same version of WP. Two of the sites work fine, and the third experiences this issue.
I go to set in the API Key and other data, hit save, but it takes me back to the same page, and nothing is saved. I've deactivated and re-activated, uninstalled and re-installed the app, and tried to bypass the admin interface by using the defines in wp-config.
When I tried the defined config, i can activate other sub-plugins.
However, when their options appear in the settings, I can't save their options either.
I have no problem saving options for other plugins.