An additional receiving routing rule has to be configured on GSuite to send a copy of all mail fowarded via catchall to the SkyConnect Server.
The steps to configure are as given below.
Go to Admin > Apps > G Suite > Gmail > Advanced Settings > Routing
Create a mail routing rule for Incoming mails
Under Messages to affect, select all options Inbound, Internal-receiving
No changes to be made to Headers ,Subject, Route, Envelope-recipient, Spam and Attachment
Under Also deliver to, select Add more recipients. In the updated dialog box, click Add
In the Add setting form, select Advanced
In the Route section, select Change route.
In the drop down list of configured routes, choose the route created in step A
Change Envelope recipients
Select the option Change envelope recipient
Choose option Replace Domain and add the Vaultastic domain name
Customize the Spam and delivery options as shown
Save the settings
Click Show options
Under the Account types to affect, select Unrecognized / Catchall option
Save the rule.