diff --git a/src/handlers/users.ts b/src/handlers/users.ts
index 5e596d1..90a7dbf 100644
--- a/src/handlers/users.ts
+++ b/src/handlers/users.ts
@@ -4,7 +4,7 @@ import adminAccessToken from '../config/synapse_access_token.json'
 import { IdMapping } from '../entity/IdMapping'
 import log from '../helpers/logger'
 import { createMembership, getUserId, save } from '../helpers/storage'
-import { axios } from '../helpers/synapse'
+import { axios, getUserDomain } from '../helpers/synapse'
 
 export type RcUser = {
   _id: string
@@ -76,7 +76,7 @@ async function registerUser(user: MatrixUser): Promise<AccessToken> {
 }
 
 async function userAlreadyExists(user: MatrixUser): Promise<boolean> {
-  const user_data = (await axios.get('/_synapse/admin/v2/users/' + user.username)).data
+  const user_data = (await axios.get('/_synapse/admin/v2/users/@' + user.username + ":" + getUserDomain())).data
   log.debug(`Mapping exists:`, user_data)
   return true
 }
diff --git a/src/helpers/synapse.ts b/src/helpers/synapse.ts
index da2bae7..8a454f3 100644
--- a/src/helpers/synapse.ts
+++ b/src/helpers/synapse.ts
@@ -14,6 +14,10 @@ export interface SessionOptions {
   [others: string]: unknown
 }
 
+export function getUserDomain(): string {
+  return "m-rc.jennett-wheeler.co.uk"
+}
+
 export { default as axios } from 'axios'
 export const whoami = () =>
   new Promise<void>((resolve, reject) => {