I had the same problem. "error: Notfound: not found"
I removed the passwords, changed everything to see if I could get it to start conning with Blogger (again). But I got nothing.
So, removed the accounts. Then tried to re-add them back to Windows Live Writer. Nothing.
Then I found this: https://productforums.google.com/forum/#!msg/blogger/-49FC2\_0l-g/ZpI3-K6YO6UJ
I was not the only person having this problem.
I waited 1/2 the day, then began moving all my blogs posts from Blogger to WordPress. I would PREFER to keep using Blogger but since they don't seem to give a care about those using their site, it looks like I will be transferring everything over to WordPress.
Only thing I am asking, is for this issue to be resolved. Blogger should get off it's rear & fix the issue. Instead of ignoring what we have to say.