In order to disable TLS from NetVault follow the below procedure
From the NetVault main menu ,go to server settings-------->Web Service
Ciphers to disable for incoming Web Service connections: To disable a cipher for incoming web service connections, enter its value given in the second column of the table as mentioned in the link https://www.openssl.org/docs/man1.0.2/apps/ciphers.html. However, if the entered cipher does not match with ciphers of incoming web service connection, no cipher is disabled. To disable multiple ciphers, enter the values separated by comma. By default, this field is blank and all the ciphers are allowed.
You can modify the Web Service configuration to disable protocols for incoming web service connections settings to prevent from allowing one or more protocols. You can configure this setting from the Change Settings page.