PAYBOX - Why are all order confirmations duplicated (Virtuemart 4)?

[@lexandre]

Hello,
After updating virtuemart to V4 (VirtueMart:4.2.0.10905_Joomla:3.10.12) I carry out PAYBOX payment tests and each order is confirmed in duplicate (double email to the customer, double email to the seller and double confirmation in order history with exactly the same information). Does anyone know where the problem could be coming from?

[@lexandre]

The problem seems to only occur on the paybox test server but not on the production server.