Update: WeChat and Microsoft resolved this issue on Monday, Jan 13.
WeChat’s browser appear to be blocking both Microsoft Forms and Microsoft Sway. Forms and Sway are both accessible in China; it is WeChat in particular that is blocking them. This will affect you if you use Forms with a QR code to collect event registration sign-ups – users will be blocked from the sign-up when they scan the code.
Unfortunately, there’s not a good workaround except to avoid using QR codes for event registration. Instead, make a short link. You need to use a Chinese service because Western shortlink services like bit.ly are blocked. Use the Chinese website http://sina.lt. This will prompt people to open a web browser, type in the URL, and the page will then load correctly in their web browser.
WARNING – do not email links created using http://sina.lt because they may be marked as spam. Instead, email the original link.