diff --git a/maubot/management/frontend/src/api.js b/maubot/management/frontend/src/api.js
index 44db7c3..d6a30dd 100644
--- a/maubot/management/frontend/src/api.js
+++ b/maubot/management/frontend/src/api.js
@@ -214,10 +214,10 @@ export async function uploadAvatar(id, data, mime) {
 }
 
 export function getAvatarURL({ id, avatar_url }) {
-    avatar_url = avatar_url || ""
-    if (avatar_url.startsWith("mxc://")) {
-        avatar_url = avatar_url.substr("mxc://".length)
+    if (!avatar_url?.startsWith("mxc://")) {
+        return null
     }
+    avatar_url = avatar_url.substr("mxc://".length)
     return `${BASE_PATH}/proxy/${id}/_matrix/media/r0/download/${avatar_url}?access_token=${
         localStorage.accessToken}`
 }
diff --git a/maubot/management/frontend/src/pages/dashboard/Client.js b/maubot/management/frontend/src/pages/dashboard/Client.js
index ac81114..806e112 100644
--- a/maubot/management/frontend/src/pages/dashboard/Client.js
+++ b/maubot/management/frontend/src/pages/dashboard/Client.js
@@ -215,8 +215,12 @@ class Client extends BaseMainView {
     }
 
     get avatarMXC() {
-        return this.state.avatar_url === "disable"
-            ? this.props.entry.remote_avatar_url : this.state.avatar_url
+        if (this.state.avatar_url === "disable") {
+            return this.props.entry.remote_avatar_url
+        } else if (!this.state.avatar_url?.startsWith("mxc://")) {
+            return null
+        }
+        return this.state.avatar_url
     }
 
     get avatarURL() {