diff --git a/app/src/main/java/io/legado/app/utils/NetworkUtils.kt b/app/src/main/java/io/legado/app/utils/NetworkUtils.kt
index bc34b15bf..ece587df0 100644
--- a/app/src/main/java/io/legado/app/utils/NetworkUtils.kt
+++ b/app/src/main/java/io/legado/app/utils/NetworkUtils.kt
@@ -185,8 +185,8 @@ object NetworkUtils {
      * @param input the address string to check for validity.
      * @return True if the input parameter is a valid IPv4 address.
      */
-    fun isIPv4Address(input: String): Boolean {
-        return IPV4_PATTERN.matcher(input).matches()
+    fun isIPv4Address(input: String?): Boolean {
+        return input != null && IPV4_PATTERN.matcher(input).matches()
     }
 
     /**