Same problem here. And guess what: I mailed them the problem and even had a print screen with the error attached as well. No answer , no nothing. I think we should report as many as we can. this is the report link: https://io.help.yahoo.com/contact/index?locale=en_US&y=PROD_MSNG&page=contact
you should select in this way:
1)select a product: messenger all
3)select category: notices and errors
4) sub-category: only one option: messenger crash or freeze.
after that you will write a short description of your problem (i wrote error 200), and after selecting and writing it, they will show up an article in case it could help. in our situation, it doesn't , so click no when you will get the pup-up of that article.
after that , you can proceed in sending your message.
hope this can help you guys in sending as many requests as we need in order to get this fixed.