diff --git a/packages/backend/server/src/plugins/calendar/providers/caldav.ts b/packages/backend/server/src/plugins/calendar/providers/caldav.ts
index e42348d4da..8c7210ede8 100644
--- a/packages/backend/server/src/plugins/calendar/providers/caldav.ts
+++ b/packages/backend/server/src/plugins/calendar/providers/caldav.ts
@@ -1020,7 +1020,7 @@ export class CalDAVProvider extends CalendarProvider {
     if (response.ok) {
       return response.url;
     }
-    if ([404, 405].includes(response.status)) {
+    if ([400, 404, 405].includes(response.status)) {
       return serverUrl;
     }
     const text = await response.text();
diff --git a/packages/backend/server/src/plugins/calendar/resolver.ts b/packages/backend/server/src/plugins/calendar/resolver.ts
index dbba85fac6..134c751fdf 100644
--- a/packages/backend/server/src/plugins/calendar/resolver.ts
+++ b/packages/backend/server/src/plugins/calendar/resolver.ts
@@ -1,6 +1,7 @@
 import {
   Args,
   GraphQLISODateTime,
+  Int,
   Mutation,
   Parent,
   ResolveField,
@@ -75,6 +76,22 @@ export class UserCalendarResolver {
 export class CalendarAccountResolver {
   constructor(private readonly calendar: CalendarService) {}
 
+  @ResolveField(() => Int)
+  async calendarsCount(
+    @CurrentUser() user: CurrentUser,
+    @Parent() account: CalendarAccountObjectType
+  ) {
+    if (typeof account.calendarsCount === 'number') {
+      return account.calendarsCount;
+    }
+
+    const calendars = await this.calendar.listAccountCalendars(
+      user.id,
+      account.id
+    );
+    return calendars.length;
+  }
+
   @ResolveField(() => [CalendarSubscriptionObjectType])
   async calendars(
     @CurrentUser() user: CurrentUser,