diff --git a/src/main/kotlin/dev/typetype/server/services/DownloaderGatewayService.kt b/src/main/kotlin/dev/typetype/server/services/DownloaderGatewayService.kt
index db47985..a2926ac 100644
--- a/src/main/kotlin/dev/typetype/server/services/DownloaderGatewayService.kt
+++ b/src/main/kotlin/dev/typetype/server/services/DownloaderGatewayService.kt
@@ -46,7 +46,7 @@ class DownloaderGatewayService(
 
     fun openFetchAbsolute(url: String, headers: Map<String, String>): Response {
         val requestBuilder = Request.Builder().url(url).method("GET", null)
-        headers["Range"]?.takeIf { it.isNotBlank() }?.let { requestBuilder.addHeader("Range", it) }
+        headerValue(headers, "Range")?.takeIf { it.isNotBlank() }?.let { requestBuilder.addHeader("Range", it) }
         return client.newCall(requestBuilder.build()).execute()
     }
 
@@ -62,4 +62,7 @@ class DownloaderGatewayService(
         val lower = name.lowercase()
         return lower != "host" && lower != "content-length" && lower != "connection"
     }
+
+    private fun headerValue(headers: Map<String, String>, name: String): String? =
+        headers.entries.firstOrNull { it.key.equals(name, ignoreCase = true) }?.value
 }
diff --git a/src/test/kotlin/dev/typetype/server/DownloaderGatewayArtifactProxyTest.kt b/src/test/kotlin/dev/typetype/server/DownloaderGatewayArtifactProxyTest.kt
index 5943c57..292a8ae 100644
--- a/src/test/kotlin/dev/typetype/server/DownloaderGatewayArtifactProxyTest.kt
+++ b/src/test/kotlin/dev/typetype/server/DownloaderGatewayArtifactProxyTest.kt
@@ -54,7 +54,7 @@ class DownloaderGatewayArtifactProxyTest {
 
         try {
             val response = client.get("/downloader/jobs/test/artifact") {
-                header(HttpHeaders.Range, "bytes=0-2")
+                header(HttpHeaders.Range.lowercase(), "bytes=0-2")
             }
             assertEquals(HttpStatusCode.PartialContent, response.status)
             assertEquals("bytes=0-2", requestedRange.get())