Some users not invited on room upgrade

[richvdh]

Steps to reproduce

1. Upgrade a room
2. Tell Element to invite everyone from the previous room

Outcome

What did you expect?

Everyone invited

What happened instead?

about 10% of users invited

Operating system

No response

Browser information

No response

URL for webapp

No response

Application version

No response

Homeserver

No response

Will you send logs?

Yes

[t3chguy]

2025-12-02T19:19:11.690Z D FetchHttpApi: <-- POST https://matrix.sw1v.org/_matrix/client/v3/rooms/!roomId/invite [436ms 403]
2025-12-02T19:19:11.691Z E MatrixError: [403] This user is not permitted to send invites to this server/user (https://matrix.sw1v.org/_matrix/client/v3/rooms/!roomId/invite)
M_FORBIDDEN: MatrixError: [403] This user is not permitted to send invites to this server/user (https://matrix.sw1v.org/_matrix/client/v3/rooms/!roomId/invite)

Looks like the last invite failed and it then gave up, M_FORBIDDEN causes it to stop entirely given typically this error being returned is irrespective of the address being invited, and has to do with your lack of permission/membership in a given room.

It is considered a fatal error which aborts later invite attempts https://github.com/element-hq/element-web/blob/develop/src/utils/MultiInviter.ts#L271-L284

This aligns with the spec definition

M_FORBIDDEN Forbidden access, e.g. joining a room without permission, failed login.

It seems like this is due to a spam check in Synapse https://github.com/element-hq/synapse/blob/develop/synapse/handlers/federation.py#L1059-L1065

[richvdh]

From my server logs:

2025-12-02 19:19:11,307 - synapse.http.matrixfederationclient - 370 - INFO - POST-20843 - {GET-O-773} [t2l.io] Completed request: 200 OK in 0.03 secs, got 25 bytes - GET matrix-federation://t2l.io/_matrix/federation/v1/query/profile?user_id=%40travis%3At2l.io&field=displayname
2025-12-02 19:19:11,335 - synapse.http.matrixfederationclient - 370 - INFO - POST-20843 - {GET-O-774} [t2l.io] Completed request: 200 OK in 0.03 secs, got 54 bytes - GET matrix-federation://t2l.io/_matrix/federation/v1/query/profile?user_id=%40travis%3At2l.io&field=avatar_url
2025-12-02 19:19:11,553 - synapse.http.matrixfederationclient - 792 - INFO - POST-20843 - {PUT-O-775} [t2l.io] Got response headers: 403 Forbidden
2025-12-02 19:19:11,554 - synapse.http.matrixfederationclient - 893 - WARNING - POST-20843 - {PUT-O-775} [t2l.io] Request failed: PUT matrix-federation://t2l.io/_matrix/federation/v2/invite/%21rh9Uxk45AsPongyP3ypgpsCmuIufiggD6mDXFWh4_FM/%24ixO1-f9GVeb6lGieOgw8ZIBchNHHQXIuaInmkrLVS_U: HttpResponseException('403: Forbidden')
2025-12-02 19:19:11,562 - synapse.http.server - 131 - INFO - POST-20843 - <XForwardedForRequest at 0x7fefe9913290 method='POST' uri='/_matrix/client/v3/rooms/!rh9Uxk45AsPongyP3ypgpsCmuIufiggD6mDXFWh4_FM/invite' clientproto='HTTP/1.0' site='8008'> SynapseError: 403 - This user is not permitted to send invites to this server/user
2025-12-02 19:19:11,565 - synapse.access.http.8008 - 521 - INFO - POST-20843 - 2001:8b0:ba7a:e98f:fd75:55c8:f135:c6f3 - 8008 - {@richvdh:sw1v.org} Processed request: 0.290sec/0.001sec (0.023sec, 0.007sec) (0.010sec/0.034sec/13) 98B 403 "POST /_matrix/client/v3/rooms/!rh9Uxk45AsPongyP3ypgpsCmuIufiggD6mDXFWh4_FM/invite HTTP/1.0" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Element-Nightly/2025120101 Chrome/142.0.7444.175 Electron/39.2.3 Safari/537.36" [0 dbevts]

@turt2live: I assume it's deliberate that @travis:t2l.io rejects invites? (MSC4380 or MSC4155?)

@t3chguy: It feels like we shouldn't abort all invites on the first failure of this nature.

[turt2live]

@turt2live: I assume it's deliberate that @travis:t2l.io rejects invites? (MSC4380 or MSC4155?)

yes, I have a badly configured MSC4155 setup (edit: this makes it hard for me to allow invites, so it just rejects everyone)