My company has software that sends files to clients’ laptops. However, I have one client who encounters issues when downloading files with the software.
Our software is written in C# and uses Chilkat Software for FTP file upload and download functions. (I’ve also tried using FtpWebRequest to send the files to the client’s laptop without success.) The attached image shows the error message they receive. The issue only occurs with their home Wi-Fi; they’ve used a hotspot and other Wi-Fi networks without issue. I’ve tried both Passive and Active modes, and I’ve added inbound and outbound rules for TCP port 21 on their laptop. I also attempted to use Telnet on port 21, but it says ‘connect failed’ regardless of the port used. The same issue occurs when using the command prompt.
I would appreciate any help.