I was able to make the connection. However it gets disconnected after few seconds or minutes and doesn't connect back again.
The logs are as below:
. 2016-08-09 19:55:44.354 --------------------------------------------------------------------------
. 2016-08-09 19:55:44.354 WinSCP Version 5.9 (Build 6786) (OS 6.1.7601 Service Pack 1 - Windows 7 Enterprise)
. 2016-08-09 19:55:44.354 Configuration: HKCU\Software\Martin Prikryl\WinSCP 2\
. 2016-08-09 19:55:44.354 Log level: Normal
. 2016-08-09 19:55:44.354 Local account: domain\username
. 2016-08-09 19:55:44.354 Working directory: C:\Program Files (x86)\WinSCP
. 2016-08-09 19:55:44.354 Process ID: 12608
. 2016-08-09 19:55:44.355 Command-line: "C:\Program Files (x86)\WinSCP\WinSCP.exe"
. 2016-08-09 19:55:44.355 Time zone: Current: GMT+1, Standard: GMT+0 (GMT Standard Time), DST: GMT+1 (GMT Daylight Time), DST Start: 27/03/2016, DST End: 30/10/2016
. 2016-08-09 19:55:44.355 Login time: 09 August 2016 19:55:44
. 2016-08-09 19:55:44.355 --------------------------------------------------------------------------
. 2016-08-09 19:55:44.355 Session name: username@servername (Site)
. 2016-08-09 19:55:44.355 Host name: scvftp.northeurope.cloudapp.azure.com (Port: 21)
. 2016-08-09 19:55:44.355 User name: username (Password: Yes, Key file: No)
. 2016-08-09 19:55:44.355 Transfer Protocol: FTP
. 2016-08-09 19:55:44.355 Ping type: Dummy, Ping interval: 300 sec; Timeout: 60 sec
. 2016-08-09 19:55:44.355 Disable Nagle: No
. 2016-08-09 19:55:44.355 Proxy: None
. 2016-08-09 19:55:44.355 Send buffer: 262144
. 2016-08-09 19:55:44.355 UTF: Auto
. 2016-08-09 19:55:44.355 FTPS: Explicit TLS/SSL [Client certificate: No]
. 2016-08-09 19:55:44.355 FTP: Passive: Yes [Force IP: Auto]; MLSD: Auto [List all: Auto]; HOST: Auto
. 2016-08-09 19:55:44.355 Session reuse: Yes
. 2016-08-09 19:55:44.355 TLS/SSL versions: TLSv1.0-TLSv1.2
. 2016-08-09 19:55:44.355 Local directory: C:\Argos, Remote directory: /, Update: Yes, Cache: Yes
. 2016-08-09 19:55:44.355 Cache directory changes: Yes, Permanent: Yes
. 2016-08-09 19:55:44.355 Recycle bin: Delete to: No, Overwritten to: No, Bin path:
. 2016-08-09 19:55:44.355 Timezone offset: 0h 0m
. 2016-08-09 19:55:44.355 --------------------------------------------------------------------------
. 2016-08-09 19:55:44.411 Connecting to ftpsitename.northeurope.cloudapp.azure.com ...
. 2016-08-09 19:55:44.471 Connected with ftpsitename.northeurope.cloudapp.azure.com, negotiating TLS connection...
< 2016-08-09 19:55:44.518 220 Microsoft FTP Service
> 2016-08-09 19:55:44.518 AUTH TLS
< 2016-08-09 19:55:44.567 234 AUTH command ok. Expecting TLS Negotiation.
. 2016-08-09 19:56:44.162 Timeout detected. (control connection)
. 2016-08-09 19:56:44.162 Connection failed.
* 2016-08-09 19:56:44.212 (EFatal) Connection failed.
* 2016-08-09 19:56:44.212 Timeout detected. (control connection)
* 2016-08-09 19:56:44.212 Connection failed.
I have set the Keepalives to 300 secs.
Using FTP protocol and Explicit encryption.
What can cause this disconnections?
Regards