diff --git a/packages/federation-sdk/src/index.ts b/packages/federation-sdk/src/index.ts
index 7bee626e..42b4069a 100644
--- a/packages/federation-sdk/src/index.ts
+++ b/packages/federation-sdk/src/index.ts
@@ -124,6 +124,10 @@ export type HomeserverEventSignatures = {
 		room_id: string; // room where the change happened
 		role: 'moderator' | 'owner' | 'user'; // 50, 100, 0
 	};
+	'homeserver.matrix.membership.rejected': {
+		event: PduForType<'m.room.member'>;
+		reason: string;
+	};
 };
 
 export { roomIdSchema, userIdSchema, eventIdSchema, extractDomainFromId } from '@rocket.chat/federation-room';
diff --git a/packages/federation-sdk/src/services/event.service.ts b/packages/federation-sdk/src/services/event.service.ts
index 9d9817bd..56aff611 100644
--- a/packages/federation-sdk/src/services/event.service.ts
+++ b/packages/federation-sdk/src/services/event.service.ts
@@ -167,12 +167,19 @@ export class EventService {
 					try {
 						await this.validateEvent(event);
 					} catch (err) {
-						this.logger.error({
-							msg: 'Event validation failed',
-							origin,
-							event,
-							err,
-						});
+						if (err instanceof Error && err.name === 'UnknownRoomError' && event.type === 'm.room.member') {
+							await this.eventEmitterService.emit('homeserver.matrix.membership.rejected', {
+								event,
+								reason: err.message,
+							});
+						} else {
+							this.logger.error({
+								msg: 'Event validation failed',
+								origin,
+								event,
+								err,
+							});
+						}
 						continue;
 					}
 
diff --git a/packages/federation-sdk/src/services/state.service.spec.ts b/packages/federation-sdk/src/services/state.service.spec.ts
index d6161451..9611aadb 100644
--- a/packages/federation-sdk/src/services/state.service.spec.ts
+++ b/packages/federation-sdk/src/services/state.service.spec.ts
@@ -2262,7 +2262,7 @@ describe('StateService', async () => {
 			expect(servers.size).toBe(1);
 		});
 
-		it('should exclude servers with non-joined members', async () => {
+		it('should include servers with banned or invited members but exclude left', async () => {
 			const { roomCreateEvent } = await createRoom('public');
 
 			const creator = '@alice:example.com'; // Room creator with admin permissions
@@ -2284,9 +2284,9 @@ describe('StateService', async () => {
 
 			expect(servers.has('joined.com')).toBe(true);
 			expect(servers.has('left.com')).toBe(false);
-			expect(servers.has('banned.com')).toBe(false);
-			expect(servers.has('invited.com')).toBe(false);
-			expect(servers.size).toBe(2); // example.com (creator) + joined.com
+			expect(servers.has('banned.com')).toBe(true);
+			expect(servers.has('invited.com')).toBe(true);
+			expect(servers.size).toBe(4); // example.com (creator) + joined.com + banned.com + invited.com
 		});
 
 		it('should return creator server for room with only creator', async () => {
diff --git a/packages/federation-sdk/src/services/state.service.ts b/packages/federation-sdk/src/services/state.service.ts
index 9eb6ba38..657568a1 100644
--- a/packages/federation-sdk/src/services/state.service.ts
+++ b/packages/federation-sdk/src/services/state.service.ts
@@ -697,8 +697,10 @@ export class StateService {
 
 		const servers = new Set<string>();
 
+		const residentMemberships = new Set(['join', 'invite', 'ban']);
+
 		for (const event of state.values()) {
-			if (!event.isMembershipEvent() || event.getMembership() !== 'join') {
+			if (!event.isMembershipEvent() || !residentMemberships.has(event.getMembership() ?? '')) {
 				continue;
 			}