I found the main culprit!   There was a sitewide link in the footer that had incorrect html formatting.  Instead of http://domainname.com, it was incorrectly inserted as domainname.com.

Thanks for the help!

I've run the crawl tests in Screaming Frog and Moz. Webmaster tools is finding these errors as well.  The sitemap is clean and void of these URLS which is strange.

Just to clarify- All the old urls are fine such as http://domainname.com/page-name .  They've all been duplicated with http://domainname.com/page-name/http://domainname

Hey there.

For some reason when doing crawl tests I'm finding pages with the domain name being tacked on the end and causing 404 errors. 
For example:  http://domainname.com/page-name/http://domainname.com

This is happening to all pages, posts and even category type

1. Site is in Wordpress
2. Using Yoast SEO plugin

Any suggestions?

Thanks!

I found the main culprit!   There was a sitewide link in the footer that had incorrect html formatting.  Instead of http://domainname.com, it was incorrectly inserted as domainname.com.

Thanks for the help!