Erreur #102 - Le URL n'est pas valide.

I have this error when trying to connect to distant list (I'm not sur of the name since I have a french version). Our site went on https (I did the change of address in preferences in MaxBulk) and since I have no access to mailing list. I did what I found on this forum 6 years ago : CHMOD the folder but I try 705, 755, no difference, what else could I do ?
thanks if anyone got an idea…
Hi Stan,
thanks for your reply. I have Maxbulk 8.5.4. And yes it's working with MLM connection with web browser, no problems. It's just in the software when I want to access to the "distant list" that I have this error. This is new since we have https instead of http.
thanks for your message, I already asked them but they don't answer so I'm stuck. It's not exactly the same URL, since it's now https instead of http, could it be the problem ? It worked fine before we moved to https.