Hi ! It was the same problem.for me.
Didn’t understood about 8xxxx limitation.message after failure because I had 26M limit to upload.
I found here about parameter port_max_size.
Not only max_upload_size cause the problem.
Check also port_max_size.
And don’t forget to RESTART httpd service
Additionally to max_upload_size I changed just here another one limit.
For last upgrade packege to 7.10.17 the 28M limit is enough.
; Maximum size of POST data that PHP will accept.
; Its value may be 0 to disable the limit. It is ignored if POST data reading
; is disabled through enable_post_data_reading.
; http://php.net/post-max-size
post_max_size = 28M