diff --git a/src/main/java/moe/yushi/authlibinjector/httpd/LegacySkinAPIFilter.java b/src/main/java/moe/yushi/authlibinjector/httpd/LegacySkinAPIFilter.java
index 4755172..dc6862c 100644
--- a/src/main/java/moe/yushi/authlibinjector/httpd/LegacySkinAPIFilter.java
+++ b/src/main/java/moe/yushi/authlibinjector/httpd/LegacySkinAPIFilter.java
@@ -16,6 +16,7 @@
  */
 package moe.yushi.authlibinjector.httpd;
 
+import static java.nio.charset.StandardCharsets.ISO_8859_1;
 import static java.util.Optional.empty;
 import static java.util.Optional.of;
 import static java.util.Optional.ofNullable;
@@ -65,6 +66,10 @@ public class LegacySkinAPIFilter implements URLFilter {
 			return empty();
 		String username = matcher.group("username");
 
+		// Minecraft does not encode non-ASCII characters in URLs
+		// We have to workaround this problem
+		username = correctEncoding(username);
+
 		Optional<String> skinUrl;
 		try {
 			skinUrl = upstream.queryUUID(username)
@@ -104,4 +109,9 @@ public class LegacySkinAPIFilter implements URLFilter {
 						.map(JsonUtils::asJsonString)
 						.orElseThrow(() -> newUncheckedIOException("Invalid JSON: Missing texture url")));
 	}
+
+	private static String correctEncoding(String grable) {
+		// platform charset is used
+		return new String(grable.getBytes(ISO_8859_1));
+	}
 }
diff --git a/src/main/java/moe/yushi/authlibinjector/internal/fi/iki/elonen/NanoHTTPD.java b/src/main/java/moe/yushi/authlibinjector/internal/fi/iki/elonen/NanoHTTPD.java
index 15dcbdb..1b72490 100644
--- a/src/main/java/moe/yushi/authlibinjector/internal/fi/iki/elonen/NanoHTTPD.java
+++ b/src/main/java/moe/yushi/authlibinjector/internal/fi/iki/elonen/NanoHTTPD.java
@@ -46,8 +46,7 @@
  */
 package moe.yushi.authlibinjector.internal.fi.iki.elonen;
 
-import static java.nio.charset.StandardCharsets.US_ASCII;
-
+import static java.nio.charset.StandardCharsets.ISO_8859_1;
 import java.io.BufferedInputStream;
 import java.io.BufferedReader;
 import java.io.ByteArrayInputStream;
@@ -360,7 +359,7 @@ public abstract class NanoHTTPD {
 				}
 
 				// Create a BufferedReader for parsing the header.
-				BufferedReader hin = new BufferedReader(new InputStreamReader(new ByteArrayInputStream(buf, 0, this.rlen), US_ASCII));
+				BufferedReader hin = new BufferedReader(new InputStreamReader(new ByteArrayInputStream(buf, 0, this.rlen), ISO_8859_1));
 
 				// Decode the header into parms and header java properties
 				Map<String, String> pre = new HashMap<>();
@@ -486,7 +485,7 @@ public abstract class NanoHTTPD {
 				}
 				if (expect100Continue && !continueSent) {
 					continueSent = true;
-					this.outputStream.write("HTTP/1.1 100 Continue\r\n\r\n".getBytes(US_ASCII));
+					this.outputStream.write("HTTP/1.1 100 Continue\r\n\r\n".getBytes(ISO_8859_1));
 				}
 			}
 			return this.parsedInputStream;