Today, i cannot connect to my QNap via FTP – Linux FileZilla always shows „Verbindungsversuch fehlgeschlagen mit „ECONNREFUSED – Verbindung durch Server verweigert“.“ on connect.

After an hour of unsuccessful googling, I found the problem: QNap AppCenter had an update for „QuFTP service“ which needed to be installed:

2024-08-29 10:13:09 [App Center] Updated QuFTP Service from 1.3.2 to 1.4.0.

After installing the update, everything is working fine again.