You can check the following steps / root causes, if you receive a white page in SupplyOn.
4. Check if your company uses ZScaler.
4.1. Login to SupplyOn and open "SupplyChainCollaboration"
4.2. Press F12 to open the "DEV Tools" of your browser
4.3. Open the tab "Network" within the DEV Tools
4.4. Open "Purchase Orders" or "Delivery Instructions" to load the white page
4.5. Click on the red message and open your "Header" Tab (see Screenshot)