If you can’t install MySOS in Japan (not outside of Japan), please install MySOS normal mode first from the App Store or Google Play. And then please convert to MySOS quarantine mode by tapping the confirmation dialog box of the purpose of use.
※You can use MySOS with the models which can use App Store, Google Play, or internet connection Google can use.
If you can't use above, please contact the HCO.
The HCO Email: app@hco.mhlw.go.jp