Failed to Connect - Error:The Parameter is incorrect

[Druffini]

Hello,

We are having issues with connecting to our FTPE server through BestSync. I tried the same login information on FileZilla and it works with no issues. I posted two screenshots below, one is of the error message I get, and the other is my profile settings and the message I get when connecting. I have tried playing with the Passive mode, Use FTP Proxy, and Product Data Channel checkboxes but they all give me the same results.

I tried this as well and still, it won't connect. https://www.risefly.com/help/wzftps.htm

We have tried this on multiple machines and on a Linux server and we still get the same error message. All of my other connections are working well, SFTP, and FTP, but the FTPE is not working.

Thank you,

[rclark]

I will add a few more details to my colleague's original post:

we have BestSync ultimate license
ftp.brentindustriesllc.com matches the name on the Sectigo certificate
we have tried with self signed certificate as well
We have the windows firewall deactivated on all clients where we test
our current testing is performed on the same subnet, so no firewall appliances are between the connections
We experience the same results on both a Synology NAS FTP host and a Linux vsftpd daemon (filezilla client works, bestsync does not work)
It appears there is instability with FTPS on this client?
It seems to be MORE unstable if we use port 990 versus 21

If you wish we can authorize your public IP addresses through our firewall and assign you a username/password for testing. if you wish to do this, please provide public IPs.

[rclark]

Is anyone there?

[RiseFly]

Sorry for replying to you late.
Please send a test account to risefly@risefly.com so we can debug with your server.

[rclark]

sent

[RiseFly]

Thank you for the test account.
I have confirmed the connection with your server.
It seems that your server does not respond to port 21 and 990,
please confirm the server setting again, if you are using the correct port.