UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2987.98 Safari/537.36

Steps to reproduce the problem:
1. Find any extension
2. Try to install it
3. You got it!

What is the expected behavior?
Extension installing completion

What went wrong?
I only got the next error message: "An error has occurred
Installation is not enabled."

WebStore page: https://chrome.google.com/webstore/category/extensions?hl=en-US and any other

Did this work before? N/A 

Chrome version: 57.0.2987.98  Channel: n/a
OS Version: Debian GNU/Linux 9 (stretch) 64-bit
Flash Version: 

This bug makes me very angry :)
 

Deleted: Screenshot from 2017-04-08 12-59-05.png 197 KB

	Screenshot from 2017-04-08 12-59-05.png 197 KB View Download