Hi Real, thank you.Hi, I have experienced the same problem. In one computer I kept on getting the same message.
However, on the other PC, I was able to save with no errors. It could be cache/Aliexpress new design issue. It is intermittent and hit or miss for some people. I'd suggest to try with different PC or devices and see if you can get it working. Or log out of Aliexpress and clear your cache and see if you can get it working.
You can even try with Internet Explorer or Firefox browser, since saving your data does not require Chrome Extensions.
The only thing it helped is the "search" button on Aliexpress to look for other sellers.I think I got this figured out.
I used another Aliexpress account, a new account that I just started to build. I logged in to that account and went back to save my supplier info and VOILA! It works!
Come to think of it, my other PC was on the new Aliexpress account when I saved it last time... So you know what? If you don't have another account, you can create one with another email.
Try and let me know.