If your user profile was switched to Lightning Experience UI (the new fancy mobile-friendly UI Salesforce has been pushing), you won't be able to use the reports functionality of Enabler4Sheets, unfortunately.
This has never worked and although we are working hard to find a way to pull reports for you - we had no luck so far, salesforce has disabled this possibility and it doesn't look like they are going to turn this back on.
What changed in the last couple of days is that we started to detect if you have Lightning Experience UI on and we'll give you a message saying that it won't work. In the previous version reports would just fail silently.
If you are sure that you don't have Lightning Experience enabled, but you are still getting this message - please let us know asap at firstname.lastname@example.org, that would mean that our Lightning detection mechanism is not working correctly.