Hello, I'm coming back to this publication to provide a solution. On some sites I had an error message every time I used the SPPB component, I saw 3 red restangles in which appeared the message e.response is undefined and above a button proposing back to admin. I searched for a long time because I use SPPB on several sites and some of them crashed with this same message. In fact, on the sites that were crashing, I was connecting using the url https://www.xyz.com. I changed my url by no longer putting the www in front (https://xyz.com) and everything went back to normal.
If this can help a Joomla fan ;-)