The cause of unexpected errors may be poor internet connections when you installed MySOS. Sorry for your inconvenience, but please uninstall and reinstall MySOS.
If you reinstall MySOS after being displayed your quarantine last date on the top screen of MySOS, please contact the Health Monitoring Center for Overseas Entrants (HCO) with your situation because
In this case, you can’t take over previous data even if you had already tapped “Report Your Health Condition” button.
The HCO Email: app@hco.mhlw.go.jp