Hi 克里斯,
As for tenant admins, they can see the service incidents which has affected their organizations in Microsoft 365 admin center
SHD, I’d like to post a screenshot about it, however, this issue does not affect my test account at present, so the screenshot is empty.

Apart from SHD, we do have a way to see all service incidents, but because of our policy, we are not allowed to post them public, so I asked you to contact your admin to check more information of your tenant in SHD, sorry about
that.
Besides, this problem has not only happened to Chinese users, our team has recently received many reports of this 503 error from all over the world.
We all hope the issue can be fix ASAP.
Best Regards,
Arck