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Event icon · error

This Error Event is part of Connect to FTP Events.

Event ID · 321400

"Could not connect to FTP server"


The error message indicates that connection to the FTP server is not established. Any further operations with remote server will fail until reconnection attempt is made.


The error may be caused by connectivity issues such as firewall or antimalware whitelisting. Make sure that local machine can connect to the remote server—no firewall is blocking outgoing connections on the client, and incoming connection at the server.

Double check that your provided username & password, fingerprint, certificate and passphrase is valid and are in supported format. To pinpoint the problem, enable connection debugging option.

If the error is due to an unsupported TLS version, ensure that you are not restricting the latest TLS version in the connection's custom options. Also, verify that your server software is updated to support the latest TLS standards.

YouTube video · Windows service automation

Event examples

See some examples of the Could not connect to FTP server Event messages:

  • Could not connect to "dc1.local". Authentication failed.
  • Could not connect to "dc.lan". Password is set, but Username is not.
  • Could not connect to "ec2-10-0-211-96.compute-1.amazonaws.com". Error: Fingerprint for algorithm SHA-256 not supported.
  • Server asks for authentication with a client certificate. Policy requires valid SSL Client certificate.
  • Certificate file "C:\Certs\client_ssl.pem" does not contain a public key and no corresponding .crt/.cer file was found.
  • TLS host certificate fingerprint is not in a correct format.
  • Connection failed. SSL3 alert read: unsupported TLS protocol version. TLS connect: error. Can't establish TLS connection. Disconnected from server.
  • Connection failed. Policy requires SSL.
  • Peer certificate rejected. Disconnected from server.
  • There are too many connected users, please try later.
  • Connection failed. A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.

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