TextToSpeechClientBuilder access denied under IIS

I got a problem for the TextToSpeechClientBuilder, it works fine in my localhost, but after I deployed to run by IIS, it failed by Access Denied.

I have made the iCloud ACD and already set the folder to Everyone and Full right, and unclicked “read only” for the folder. I have tried to use System.IO to read the credential file and it works good. But when use TextToSpeechClientBuilder.Build, it failed as the log:

MyCalbee_1-1719283868529.png

Can anyone help me? Thanks!