Publishing error using Robohelp 2019 | Responsive HTML5 output to FTP
I am currently using RH 2019.0.14.
I am trying to publish Responsive HTML5 output to our FTP server. I successfully generated output but when I try to publish it, the following message remains there:

After some time, the Application Error message appears:

and then the following message is displayed:

The Publish Log some times displays this error:

and some times it displays this error:

I will appreciate if any body guide me to the resolution of this problem.
