I did a couple changes to give sudo user the permissions successfully to the mounted encrypted vault:
allow_rootandallow_othercannot be used as [custom mount flags without enabling (uncommenting)user_allow_other` option in /etc/fuse.conf configuration file.
sudo nano /etc/fuse.conf
GNU nano 7.2 /etc/fuse.conf
# The file /etc/fuse.conf allows for the following parameters:
#
# user_allow_other - Using the allow_other mount option works fine as root, in
# order to have it work as user you need user_allow_other in /etc/fuse.conf as
# well. (This option allows users to use the allow_other option.) You need
# allow_other if you want users other than the owner to access a mounted fuse.
# This option must appear on a line by itself. There is no value, just the
# presence of the option.
user_allow_other
# mount_max = n - this option sets the maximum number of mounts.
# Currently (2014) it must be typed exactly as shown
# (with a single space before and after the equals sign).
#mount_max = 1000
Under ‘Show Vault Options’ > ‘Mounting’
Under ‘Custom mount flags’, there is a default value