diff --git a/app/src/main/java/io/legado/app/data/entities/BookSource.kt b/app/src/main/java/io/legado/app/data/entities/BookSource.kt
index 6a373bdef..ff4eaa533 100644
--- a/app/src/main/java/io/legado/app/data/entities/BookSource.kt
+++ b/app/src/main/java/io/legado/app/data/entities/BookSource.kt
@@ -68,7 +68,7 @@ data class BookSource(
 
     fun getHeaderMap(): Map<String, String> {
         val headerMap = HashMap<String, String>()
-        headerMap["User-Agent"] = App.INSTANCE.getPrefString("user_agent") ?: userAgent
+        headerMap["user-agent"] = App.INSTANCE.getPrefString("user_agent") ?: userAgent
         header?.let {
             GSON.fromJsonObject<Map<String, String>>(header)?.let {
                 headerMap.putAll(it)
diff --git a/app/src/main/java/io/legado/app/help/storage/OldRule.kt b/app/src/main/java/io/legado/app/help/storage/OldRule.kt
index 7418ea6c6..135d604b9 100644
--- a/app/src/main/java/io/legado/app/help/storage/OldRule.kt
+++ b/app/src/main/java/io/legado/app/help/storage/OldRule.kt
@@ -131,7 +131,7 @@ object OldRule {
 
     private fun uaToHeader(ua: String?): String? {
         if (ua.isNullOrEmpty()) return null
-        val map = mapOf(Pair("User-Agent", ua))
+        val map = mapOf(Pair("user-agent", ua))
         return GSON.toJson(map)
     }