This problem was fixed thanks to Pier, a customer with a lot of experience in front end development. Thanks a lot!
A customer let me know that the control panels stopped working with the latest Google Chrome version (on Mac Version 77.0.3865.90). A fix will come asap, in the meanwhile try to install the previous version (74.0.3729.169): For Mac and for windows.
Google has broken the MIDI API support on the new version, let’s hope the next version will fix that problem.