diff --git a/src/main/kotlin/mara/server/domain/user/UserService.kt b/src/main/kotlin/mara/server/domain/user/UserService.kt
index 52ec7db..ccf62b1 100644
--- a/src/main/kotlin/mara/server/domain/user/UserService.kt
+++ b/src/main/kotlin/mara/server/domain/user/UserService.kt
@@ -41,7 +41,7 @@ class UserService(
         val newUser = createUser(user)
 
         var authId = newUser.kakaoId.toString()
-        if (newUser.googleEmail != null) authId = newUser.googleEmail!!
+        if (newUser.googleEmail != null && newUser.googleEmail != "") authId = newUser.googleEmail!!
 
         SecurityContextHolder.getContext().authentication =
             UsernamePasswordAuthenticationToken(authId, newUser.password)