diff --git a/src/utils/base64.ts b/src/utils/base64.ts
index 33814b4d..17d2806c 100644
--- a/src/utils/base64.ts
+++ b/src/utils/base64.ts
@@ -17,7 +17,7 @@
 import { createHash } from 'crypto';
 
 export function fromB64Url(input: string): Buffer {
-  return Buffer.from(input, 'base64url');
+  return Buffer.from(input, 'base64');
 }
 
 export function toB64Url(buffer: Buffer): string {