I never had this problem before since I upgraded 3.1.6. My old board is missing files and not show new images not old images, so I install new one and then it starts the problems that why I thought 3.1.6 was causing the problem because I don't change any zilla or server setting years by years.
I use file zilla, Dreamweaver and Cyberduck to upload extension. I get this error. Nothing is wrong from the host end. I change difference computer, difference place and difference IP, but the error is the same. Why ? I didn't change any setting or password?