Cannot get subEntityId on MS Teams tab app from deep link - microsoft-teams

Question

I cannot retrieve a subEntityId on a Teams tab app from a deep link. It's always empty in getContext. Could anyone please help me out?
I generated a deep link as following this page, https://learn.microsoft.com/en-us/microsoftteams/platform/concepts/build-and-test/deep-links
The link looks like this,
https://teams.microsoft.com/l/entity/58061894-78f0-49c3-99d7-25830d1c84f0/anpi-personal&context=%7B%22subEntityId%22:%22task123%22%7D
The link works as it expected, it brings me to the tab app on Teams. But no subEntityId.
The manifest of the tab app looks like this,
{
"$schema": "https://developer.microsoft.com/en-us/json-schemas/teams/v1.7/MicrosoftTeams.schema.json",
"manifestVersion": "1.7",
"version": "1.0.0",
"id": "58061894-78f0-49c3-99d7-25830d1c84f0",
"packageName": "something.package.name",
"developer": {
"name": "dev",
"websiteUrl": "some url",
"privacyUrl": "some url",
"termsOfUseUrl": "some url"
},
"icons": {
"color": "color.png",
"outline": "outline.png"
},
"name": {
"short": "some name",
"full": "some text"
},
"description": {
"short": "some text",
"full": "some text"
},
"accentColor": "#FFFFFF",
"staticTabs": [
{
"entityId": "anpi-personal",
"name": "app name",
"contentUrl": "https://exmample.com/Default.aspx?entityId={entityId}&subEntityId={subEntityId}",
"scopes": [
"personal"
]
}
],
"permissions": [
"identity",
"messageTeamMembers"
],
"validDomains": [
"foo.com"
],
"webApplicationInfo": {
"id": "13958568-6984-47d4-910f-7bb9c87078c2",
"resource": "api://exmample.com/13958568-6984-47d4-910f-7bb9c87078c2"
}
}

Answer 1

I think you need to change:
...anpi-personal&context=%7B%22subEntityId%22:%22task123%22%7D
to:
...anpi-personal?context=%7B%22subEntityId%22:%22task123%22%7D
the change is hard to see - I've changed "&context" to "?context" - "&" is required if you have -multiple- values you're passing (like "weburl=something" AND "context=something"), but in this case you only have "context", so it needs to start with "?"