Cannot connect to FTP using explicit FTP over TLS

I try to connect to a FTP folder with the following specifications:
WinSCP Version 5.16.2 RC (Build 10017)
Windows Server 2016 Standard. Version 1607
FTP, using explicit FTP over TLS and port 990
GUI, commander interface

It fails directly and I get the following error message:
"TLS connect: error in error
Can't establish TLS connection
Disconnected from server
Connection failed."

It worked with FileZilla version 3.46.3.

Hello, I was able to connect. The error comes from the fact than when I select explicit it reset the port 990 I put. And when I put port 990, the encryption changes to Implicit.

Elie wrote:

Hello, I was able to connect. The error comes from the fact than when I select explicit it reset the port 990 I put. And when I put port 990, the encryption changes to Implicit.

And that's correct. Port 990 is for implicit TLS/SSL. Explicit TLS/SSL uses port 21. If your server is configured to use explicit TLS and port 990, it's misconfigured.

Thanks for your answer Martin. So the configuration I received is wrong.

I have to connect to a FTP-Server which is not under my control and allows only explicit over port 990.
So for this I cannot use WinSCP and have to take for example Filezilla which allows such a connection.

MAEG wrote:

I have to connect to a FTP-Server which is not under my control and allows only explicit over port 990.
So for this I cannot use WinSCP and have to take for example Filezilla which allows such a connection.

WinSCP does not restrict you anyhow in ports you want to use. The only hitch is that after you type port number 990, WinSCP will select the "Implicit" encryption (as that's the correct combination). So which back to "Explicit", if your server has this strange set up.