Problem to upload .pbix file with SecureConnectionLevel=3 (rsreportserver.config)

I changed my Power BI Server config file (rsreportserver .config) to use SecureConnectionLevel value = 3 and I can´t upload a .pbix file after that.

The message error showed directly from WebUrl is: "There was an error uploading your .pbix file. Verify that the file has not been corrupted and that the file extension matches the format of the file"

If I try to open the report file from Power BI Desktop, the message is: "Unexpected error encountered"

If I back the configuration file to SecureConnectionLevel value = zero, the error do not occur.

How can I solve this problem?

Both Version (Server and Power BI Desktop) are May 2020