diff --git a/SDWebImage/SDImageCacheConfig.m b/SDWebImage/SDImageCacheConfig.m
index db4b194b..84123581 100644
--- a/SDWebImage/SDImageCacheConfig.m
+++ b/SDWebImage/SDImageCacheConfig.m
@@ -50,7 +50,7 @@ static const NSInteger kDefaultCacheMaxCacheAge = 60 * 60 * 24 * 7; // 1 week
     config.maxCacheSize = self.maxCacheSize;
     config.maxMemoryCost = self.maxMemoryCost;
     config.maxMemoryCount = self.maxMemoryCount;
-    config.namespacePrefix = [self.namespacePrefix copyWithZone:zone];
+    config.namespacePrefix = self.namespacePrefix;
     config.fileManager = self.fileManager; // NSFileManager does not conform to NSCopying, just pass the reference
     config.memoryCacheClass = self.memoryCacheClass;
     config.diskCacheClass = self.diskCacheClass;
diff --git a/SDWebImage/SDWebImageDownloaderConfig.h b/SDWebImage/SDWebImageDownloaderConfig.h
index ca41767b..1b5d833e 100644
--- a/SDWebImage/SDWebImageDownloaderConfig.h
+++ b/SDWebImage/SDWebImageDownloaderConfig.h
@@ -67,7 +67,7 @@ typedef NS_ENUM(NSInteger, SDWebImageDownloaderExecutionOrder) {
  * Set the default URL credential to be set for request operations.
  * Defaults to nil.
  */
-@property (nonatomic, strong, nullable) NSURLCredential *urlCredential;
+@property (nonatomic, copy, nullable) NSURLCredential *urlCredential;
 
 /**
  * Set username using for HTTP Basic authentication.
diff --git a/SDWebImage/SDWebImageDownloaderConfig.m b/SDWebImage/SDWebImageDownloaderConfig.m
index 393d6e06..79e15c9d 100644
--- a/SDWebImage/SDWebImageDownloaderConfig.m
+++ b/SDWebImage/SDWebImageDownloaderConfig.m
@@ -37,9 +37,9 @@ static SDWebImageDownloaderConfig * _defaultDownloaderConfig;
     config.sessionConfiguration = [self.sessionConfiguration copyWithZone:zone];
     config.operationClass = self.operationClass;
     config.executionOrder = self.executionOrder;
-    config.urlCredential = [self.urlCredential copyWithZone:zone];
-    config.username = [self.username copyWithZone:zone];
-    config.password = [self.password copyWithZone:zone];
+    config.urlCredential = self.urlCredential;
+    config.username = self.username;
+    config.password = self.password;
     
     return config;
 }