We weren't able to reproduce the issue at our end but here are a few possible options you can try:
1) Try opening your MATLAB Online in a different browser after clearing the cache and cookies for the website.
2) Ensure that the Visibility and Enable tickboxes are marked check in the Interactivity pane of the button.
3) You can try running the following commands in your MATLAB Session before running any other commands
wm = matlab.internal.webwindowmanager.instance;
wm.setStartupOptions('ExternalProcess', '--proxy-server=direct:// --proxy-bypass-list=');