Possible fix for https://github.com/firefly-iii/firefly-iii/issues/8977

app/Http/Middleware/VerifyCsrfToken.php

@@ -28,4 +28,8 @@ use Illuminate\Foundation\Http\Middleware\VerifyCsrfToken as Middleware;
 /**
  * Class VerifyCsrfToken.
  */
-class VerifyCsrfToken extends Middleware {}
+class VerifyCsrfToken extends Middleware {
+    protected $except = [
+        'oauth/token',
+    ];
+}