Sporadic connection fails

[JonFP]

I set up a new connection profile today to a server that I already have other connections to.

All the others work fine. But this new one will fail the connection sometimes with the message "Not connected ... No response from server.

Immediately clicking on the connection again usually fixes it - but I've had to do it up to four times to get a connection to work.

Anyone got any idea why this happens? As best I can see the connection definition is identical to the others for this server and they never exhibit this problem.