Couldnt get into Blogger using Windows Live Write after Googling for help on this problem. For some years. Just tried again just now 'cause trying to blog about a recent holiday trip.
Found that I have to allow access to "Less Secure Apps". Looked all over but couldnt find this settings, security, account permissions. Then, desperate for anything, I went into review of one's security setup. Going through the review of account settings, security check-up, get started, and there it was : "Access for less secure apps". Enabled it and eureka! WLW is now nicely re-married to one of my many blogs.
Might be a no-brainer for nerds and geeks, but a struck gold situation for me.
Now, another problem : have to re-learn using WLW to post on Blogger.