I noticed comments were closed without a resolution for this issue.
I tired every combination of possibilities and was unable to leave a comment on a Blogger site. What I’m hoping is to be able to leave a comment on Blogger from my WordPress to be able to share with other bloggers.
The resolution must come from Blogger’s end of things and not this end. It’s how Blogger software is set up. Trying to post comments on Blogger blogs is a drag. Open ID fails more often than it works. Blogspot software thinks we all have a single username here at wordpress.com and a single blog by the same matching name. It will not accept any other URL. So if we have a domain or more than one blog registered under the same WordPress.com username trying to comment becomes impossible.
Unless the blogger chooses to enable commenters to post with a username and URL on their Blogger blog it’s next to impossible to leave a comment. The only workaround is to register a Blogger blog which will allow you to comment but your username will not be linked to your WordPress.com blog when you do.