Unable to receive message: AccountSettings

[SlavaC1]

We are using Miracle API to communicate with FileZilla server on Windows Server 2019. We see that occasionally we get Unable to receive message: AccountSettings exception. We see that it's from ReceiveMessage() method. What could be the reason?

[PolarbearDK]

You do not write what operation you are performing when you get this error. I assume it is GetAccountSettings(), Right?

The protocol basically works this way:

Send "Give me A"
Loop: Read message 
  If Message is "A" return it 
Try again  

FileZilla sometimes sends some status messages that you have not asked for, so we retry to skip those, but only 10 time per default. If FileZilla has more than 10 messages pending then you will never get to "A" and you get the exception.

Are you keeping the FileZilla connection open for a long time? You should not do that. Instead connect, do your stuff and close connection.

If issue is not resolved, then you can try increasing fileZillaApi.ReceiveMessageRetryCount to a value greater than 10.

[SlavaC1]

We are calling SetAccountSettings() and GetAccountSettings(). Each of them throws this exception.

We noticed when giving our own TextWriter to the API and writing to logs, the problem disappears. I'm guessing that the writing to log adds a certain delay by writing the dumps Hex.Dump(Log, bytes, 1024); in LogData() in SocketCommunication class.

Also we noticed that sometimes we receive ~300 or ~400 messages, so I'm not sure that increasing retry to this amount is a good idea.

What do you think about adding a delay (sleep) in between the retries? Could it simulate the delay caused by hex dump and solve the problem? Any other idea would be apricated.