I can't upload images in the Frontend composer

Hello,

It is not possible to upload an image on Media Manager. I have found many issues similar to mine:

• I uninstalled AdminTools.
  
• I try protostar template.
  

But I still have some errors.

Checking the developer console of my web browser. I have found two errors:

• Mixed content: because there are some http URL instead of https (http://fonts.gstatic.com/s/materialicons/v12/2fcrYFNaTjcS6g4U3t-Y5ZjZjT5FdEJ140U2DJYC3mY.woff2)
  
• A Javascript uncaught error. (attached on this issue)
  

Best Regards.