If it is a yellow code caused by entering an epidemic area or contacting with a suspected case, it needs to be isolated according to the regulations, the source and daily health status should be declared in a small program, and the relevant staff should be registered, so that the yellow code will automatically become a green code if there is no abnormality in 14 days.
If the health code turns yellow for no reason, you can open the health code, find the "self-complaint" in the upper left corner, click the complaint, or uninstall and reinstall the applet to view it.