Can several people share the same home tag?
Only if the action lives in the home system rather than on one phone. A tag configured inside one person's application does nothing for anybody else, and the tag looks identical either way, which is what makes this confusing to diagnose.
Where the action lives
If the automation was configured on your phone, that phone is the only one that recognises the tag. Everyone else taps it and gets nothing.
If the tag holds an address that instructs the home system, anyone can tap it, because nothing has to be configured on their device.
The tag is identical in both cases. That is why a household concludes a tag is broken when it is simply personal.
So the first question when a tag works for one person is not what is wrong with the other phone. It is where the automation lives.
Accounts and permissions
Home systems generally have a notion of members, and members have permissions.
A partner or a flatmate needs an account with rights to the devices concerned, which is a setup step people skip because it feels like paperwork.
Children often need a restricted account rather than a full one, which is worth arranging deliberately rather than by sharing a login.
And departures need attention. Someone who moves out keeps their access until it is removed, and a tag by the door is a reminder that nobody thinks to act on.
Guests are different again
A guest has no account, no application and no interest in installing one.
The only thing that serves them is a tag opening a page that acts, or that shows information they can use.
Keep the address unguessable if it performs an action, since anyone who reads the tag has it. Treat the address as public, because it is.
And label it, since a guest will not tap an unlabelled object in someone else's house.
Making it work for a household
Put the actions in the home system rather than in a phone, always, when more than one person lives there.
Give the tag a name that means something to everyone, written on it.
Let anyone edit the scene, so the person it annoys can fix it rather than complaining to you.
And keep the physical controls working, because an automation that only some of the household can use must not be the only way to do something.
Frequently asked questions
Why does the tag only work for me?
Because the automation lives on your phone rather than in the home system. The tag is identical for everyone and the configuration is not.
Do others need an account?
For system based actions, yes, with permissions for the devices concerned. Sharing one login instead causes problems later.
Can a guest use it?
Only if the tag opens something that acts without their configuration. Treat the address as public, because anyone who taps has it.
What about someone who moves out?
Remove their access explicitly. It persists until somebody does, and nobody is reminded by a tag on a wall.