Are Incorrectly Set Up URL Rewrites a Possible Cause of Panda

[ABK717]

On a .NET site, there was a url rewrite done about 2 years ago. From a visitor's perspective, it seems to be fine as the urls look clean. But, Webmaster tools reports 500 errors from time to time showing /modules/categories... and /modules/products.... which are templates and how the original urls were structured. While the developer made it look clean, I am concerned that he could have set it up incorrectly. He acknowledged that IIS 7 on a Windows server allows url rewrites to be set up, but the site was done in another way that forces the urls to change to their product name. So, he has believed it to be okay.

However, the site dropped significantly in its ranking in July 2013 which appears to be a Panda penalty. In trying to figure out if this could be a factor in why the site has suffered, I would like to know other webmasters opinions. We have already killed many pages, removed 2/3 of the index that Google had, and are trying to understand what else it could be.

Also, in doing a header check, I see that it shows the /modules/products... page return a 301 status. I assume that this is okay, but wanted to see what others had to say about this.

When I look at the source code of a product page, I see a reference to the /modules/products...

I'm not sure if any of this pertains, but wanted to mention in case you have insight. I hope to get good feedback and direction from SEOs and technical folks

[DJ123]

Check your backlink profile - are there unnatural links?  Are there sites which are spammy linking to you?

Get your site all working technically speaking, which it sounds like you have and then or at the same time check the links.  I suspect you have some bad links which you are going to have to try to remove, or disavow.

Best of luck!

[ABK717]

I don't think you understood the question as it didn't have much to do with links. This is related to a content management system which has an ugly url which a developer then took to make it more user friendly. While a user browsing the site sees clean URLs, webmaster tools reported 500 errors which are essentially server errors.

It doesn't seem those errors are in the console anymore. But, I was wondering if anyone has seen sites receive penalties because of a handful of 500 errors even though the site looks pretty good from a user perspective. (Note: the site is fairly large and a few 500 errors appeared).