@Frank Hsieh Could you please share more details? You have mentioned, "But when the board stand alone running without debugging, the HTTP Post cannot send to the server." Do you also see any specific errors?
Are you following this documentation? https://learn.microsoft.com/en-us/samples/azure/azure-sphere-samples/https-curl-multi/
Have you enabled application development? if you have not already done so, you can enable by entering the azsphere device enable-development command at the command prompt.