Technical Tip: Getting 'The product serial number has already been registered' error while trying to activate the FortiGate

[Pavan_Chintha]

Description	This article describes how to resolve an issue while setting up FortiGate where the user is trying to activate the FortiGate in the GUI and the user has already registered on the Support Portal. Trying to activate results in the error: 'The product serial number has already been registered'.
Scope	FortiGate.
Solution	Verify if the FortiGate has an active internet connection: execute ping 8.8.8.8 execute ping 1.1.1.1 Verify if the DNS server can resolve the FortiGuard domains and reach them: execute ping service.fortiguard.net execute ping update.fortiguard.net execute ping guard.fortinet.net Check if there is connectivity to the FortiGuard servers. Refer to the article below for more guidance: Troubleshooting Tip: Unable to connect to FortiGuard servers  Run the commands below in the CLI of the FortiGate and wait till the update is successful: diagnose debug application update -1 diagnose debug enable execute update-now Try to activate the FortiGate again. Refer to the guide below for more guidance: Registering FortiGate  Note: Turn on the 'sign in FortiGate Cloud using the same account and enable management'. This will merge the FortiGate Cloud account and FortiCare account to use the same user and password and enable management.