This has been happening to me occasionally for the past couple of weeks, and now it's been ongoing all day today.I have not been able to log in for the past several hours and it's starting to get really frustrating. I've got time from work to do some adventures and collect eggs during the event, and I am not able to because even though you've been "aware of the issue" for nearly a month, it still has not been fixed.
And of course after posting this I tried one more time and was able to finally log in. But can only think how many BKs I could have run and tagged in the past 8 or 9 hours if I'd been able to play.