Troubleshoot the cause of your connection issues by following the below options.
1) In order for Repetier-Host to properly connect, the right COM Port must be selected.
2) To check on which COM port you are connected to, open "Devices and Printers" on your computer. The 3D printer will be listed under "Unspecified".
3) Seeing an exclamation mark? This means you do not have the RAMBo Driver installed onto your computer yet. Please see solution Installing the RAMBo Driver.
1) Error notifies user port access is denied. Please see solution Repetier-Server.
Please open a Tech Ticket if you have any questions or need assistance with this process.