NFS troubleshooting failure

I can able to mount the opt directory in all app servers and the file I created in one of the app-server is reflected / visible from other app-servers too. but the result was failed .
I also added /etc/fstab for permanent nfs solution. but in vain. Please let me know what went wrong in my solution.

PFA screenshots.

Its late, however if you still need help with this I think you added an extra folder at the end called webapp. It should have been directly mounted to /var/www/html like this

mount -t nfs -v server IP:/webdata /var/www/html