This was problem with the directory permissions where cacert.pem file was stored.
The directory on the client machine had the permissions "drwx------" but the correct permission required was "drwxr-xr-x" this.
I changed the directory permissions where cacert.pem file is stored on client machine to "drwxr-xr-x" and now there is no delay. This problem is fixed now.
Thank you very much.