HTTP proxy response : 407 Proxy Authorization Required (Failed)

Hello,
We have a problem with our powershell script, it works well in manual mode, but after automatisation we found that sometimes the job crached.
After checking the log files, we found that the FTP connection with the client is established successfully, but it crached when start browsing to target folder.
To unblock the situation, we execute winscp manually with GUI and after that, the automatisation job works fine.
You can find attached the two log files ;
- One before running winscp manually (job crached).
- Second after running manually (job work fine).
Tanks for your help !
WinSCP Version 5.15.1 (Build 9407)

We cannot tell why your proxy responds differently to the same requests.
Please contact your network administrator.