403.18 Cannot execute requested URL in the current application pool

Due to heavy load on web site which is configured on webfarm in remote share environment started giving below error on all servers.

After lot of googling also I haven’t got any appropriate solution

So tried below steps and it worked 

1. Created new app pool with same framework and credentials.
2. Assigned the newly created pool to the website
3. Tried by browsing and it started working.

So according to my experience we need to created new app pool to resolve the 403.18 Error.