Verify that the connection between the AS and OS stations is correctly configured in NetPro. Ensure that the S7 connection is properly established and the IP addresses match the network configuration. Check that the .xdb file for the OS station is correctly imported. To do this, open the Station Configuration Editor on the OS PC, select "Import Station," and browse to the .xdb file associated with the OS station. The path to the .xdb file can be found in the "Configuration" tab of the OS station's object properties in Simatic Manager. Ensure the correct adapter is selected in Tag Management and verify that the correct S7 access point is set in "Set PG/PC Interface." For PLCSIM.

Hope it helps you!