I have designed a layout in VSP Designer, but the print preview is different to the print result in my VertiGIS Studio Web app. What might be the problem and how can I solve it?

This is likely because the VSP Designer preview functionality does not currently (as of VSP 5.24) use the VSP Engine Tool Print Task to generate a preview, but instead uses the native VSP Designer preview functionality with the Chromium printer. This functionality will be changed in a future VSP version.