diff --git a/src/client/SinglePlayerModal.ts b/src/client/SinglePlayerModal.ts
index 6e42f523e..b1030c21f 100644
--- a/src/client/SinglePlayerModal.ts
+++ b/src/client/SinglePlayerModal.ts
@@ -73,7 +73,7 @@ export class SinglePlayerModal extends LitElement {
                               .selected=${!this.useRandomMap &&
                               this.selectedMap === mapValue}
                               .translation=${translateText(
-                                `map.${mapKey.toLowerCase()}`,
+                                `map.${mapKey?.toLowerCase()}`,
                               )}
                             ></map-display>
                           </div>