Unable to post to a Blogger blog via email - workaround
This morning I was unable to post to some of my blogs via email. I tried again and tried all of the usual suspect workarounds, but nothing worked. What did finally work was to change the secret codes associated with email posting for the blogs. That did the trick and now all is wonderful in the world again.
As I migrated some of my blogs to the new version of Blogger I did get a polite email from Blogger informing me that the prefix for the email posting addresses was changing in some cases, but I didn't see any hint that my secret code words would also need to change and in fact the email explicitly said they wouldn't be changing. Further, the blog I was having trouble with had not yet been migrated.
But, at least we now have a known workaround.