Could not retrieve directory listing and waiting for user

Hi,
I am using WinSCP 5.9.3.
In uploading (not in background, I get sometimes the error 450 'operation failed'.
Could not get directory listing.
Then WinSCP is waiting for the user to click on 'Again' and then it continues.
So, I can't upload automatically. I always have to be there.
But what is wrong and how can I solve it to upload automatically without clicking 'Again'?
Thanks,

Pieter

Thanks for your report.
I have never seen this before.
What FTP server is that?
Can you attach a complete log file (as a plain text)?

martin wrote:

Thanks for your report.
I have never seen this before.
What FTP server is that?
Can you attach a complete log file (as a plain text)?

It is LiveDrive with account Suite for 5 TB.

Then you should better contact their support.

My guess is that the server occasionally runs out of free data connection port numbers.

But anyway, WinSCP should reconnect automatically (after an interval), doesn't it?

martin wrote:

Then you should better contact their support.

My guess is that the server occasionally runs out of free data connection port numbers.

But anyway, WinSCP should reconnect automatically (after an interval), doesn't it?

Ok thanks, I will contact LiveDrive.
In other situations there is another pop screen of WinSCP which says 'Abort connection' or 'Reconnect in xx seconds'. Then WinSCP does reconnect automatically.
The issue that I described above is with another screen, which I have to click on 'Opnieuw' (Again).

Thanks so far.
Pieter

Can you attach a screenshot of the message?