Diagbox relies on a local web-server structure to display data. If the service isn't running, the software can't "access" the data it needs. Press Ctrl + Shift + Esc to open Task Manager.
Several factors contribute to the Diagbox data access problem. Some of the most common causes include:
DiagBox requires a specific "profile" (like Profile 01) to be active. If the manual activation process was interrupted, data access is restricted. Software Version Mismatch: Newer cars (post-2016) often require versions v7.83 or higher