UPDATE! Blizzard has given the all-clear and it should be safe to play again.
If you continue to encounter issues, please post in #technical-support.
Original Post
Hey everyone, I can confirm that Blizzard is aware of the issues with logging onto any Blizzard game and is working on it. If you are able to log on, I strongly recommend avoiding Competitive Play until the all-clear is given.
https://twitter.com/BlizzardCS/status/1514381063031865344?s=20&t=Ija93MALVZqgeEeNK_PTgQ
Cheers! (^^)v