This might sound like a strange question. Maybe it's a dumb one, I don't know.
Over the last two months, I've collected over 5000 verified backlinks for one (multi-tier) project. The links or articles are still there (re-verified), but I don't know whether the (ca. 3000 accounts) are still active and could be used to re-post.
Now, I know I could just not care and let the system try to post a new article to the full list, but I'd like to do a hand-selection and editing some of the old posts if possible, if they look like a good environment. But I'm sure that many of those 3k accounts will not allow me to log in, because they've been set up on a different proxy or just have been inactive for too long etc. etc. Also, I don't have access to all the emails anymore to save them.
So here's the question: how can I run some sort of quick "can I still login into those accounts?"-check?