I notice that when you change your region (for example Vietnam to Australia), Apple Music stopped picking up my family subscription and asked for a new one. This problem happened last year when I changed my account's region to New Zealand, got locked out of iCloud+ services until a week later.
See: Legal - Apple Media Services - Apple
"All Family members must share the same Home Country."
It sounds like you are not the Organizer. Even if you were, you would have to cancel your iCloud+ subscription in the first country and take out a new one in the new country. The support article Change your Apple ID country or region - Apple Support describes how to change your country setting on everything using your Apple ID, and the requirements and results of doing this.
See: Legal - Apple Media Services - Apple
"All Family members must share the same Home Country."
It sounds like you are not the Organizer. Even if you were, you would have to cancel your iCloud+ subscription in the first country and take out a new one in the new country. The support article Change your Apple ID country or region - Apple Support describes how to change your country setting on everything using your Apple ID, and the requirements and results of doing this.
Have you changed your family's region as well? You can only use a family subscription when in the same region
Is there a wait time before you could use iCloud+ services when changing your account's region?
