diff --git a/lib/selectors/keyserver-selectors.js b/lib/selectors/keyserver-selectors.js
--- a/lib/selectors/keyserver-selectors.js
+++ b/lib/selectors/keyserver-selectors.js
@@ -22,11 +22,11 @@
   _memoize(baseCookieSelector);
 
 const cookiesSelector: (state: AppState) => {
-  +[keyserverID: string]: string,
+  +[keyserverID: string]: ?string,
 } = createSelector(
   (state: AppState) => state.keyserverStore.keyserverInfos,
   (infos: { +[key: string]: KeyserverInfo }) => {
-    const cookies = {};
+    const cookies: { [string]: ?string } = {};
     for (const keyserverID in infos) {
       cookies[keyserverID] = infos[keyserverID].cookie;
     }