Webmaster Tools - URL Parameters Settings Do Not Work
- by David
Google Webmaster Tools shows problems with duplicate title tags under Optimization - HTML Improvements, for example:
???????? Mitsubishi Electric Mr. Slim PC Series PC-3KAKLT (220V) 30000 BTU
>  /????-????/mitsubishi-mr-slim-pc3kaklt-30000-btu.html
>  /????-????/mitsubishi-mr-slim-pc3kaklt-30000-btu.html?category_id=96
These two pages have exactly the same content, a rel-canonical tag is set, and they are (no longer) linked to internally. Additionally, we used the Configuration - URL Parameters setting, to set this parameter to No: Doesn't affect page content about one month ago. 
However, Google is still showing these HTML improvements (and rankings dropped dramatically). 
What else can we do here?
Best,
David