We use FTP to send data (XML) from one server to another. Basically, there is a scheduled task at server A, which uploads XML files whenever there are available, to server B by using FTP. Since this is a scheduled task, the parameters being used (e.g. login, password) remain the same at all times.
This works perfectly, except sometimes the FTP user gets refused access for a certain amount of time, for no specific reason. When I look into the log file, I can see a 530 An+error+occurred+during+the+authentication+process error happening for approximately almost an hour (this is varrying) until the FTP User is able to login succesfully again.
I'm really clueless about why this is happening. It looks like the FTP user gets banned for a certain time, but I don't think that's the case since there is really no reason for it. The only restriction I set up is allowing access from specific IP addresses, but the IP address did not change either and is correct. We also use the setting Windows credentials only.
And this happens every 3 - 4 days, there is really no pattern in it.
Does anyone have an idea what could be causing this? Is there any way to obtain a more detailed error description than An+error+occurred+during+the+authentication+process?