I just did a clean installation of 8.4, but when trying to upload images through the File Manager, I get an error message. (Even with a 13KB PNG, no success.)

In pre-7.x PHP, the error message is simply [object Object]. In 7.0 and 7.1, the error message is [Invalid JSON Response from server.] I have a number of successful installs of concrete5 of earlier versions (up to 8.31) on the same VPS server with the same PHP settings, in which the File Manager operates just fine.

Any help would be greatly appreciated.

Thanks.