E-signature error: Bad request

Scenario

Causes

The client's record in Onvio doesn't specify a Tax Matters Contact relationship.
The client's Tax Matters Contact in Onvio is an entity, when it should be an individual.
Client Centre access has not been enabled for the Tax Matters Contact.

Solution

In Onvio, select Setup > Clients from the menu bar.
Select the Edit button to the left of the client's name.
Select the Relationships tab. Make sure that an individual has been set up as the Tax Matters Contact.
Select Setup > All Contacts from the menu bar.
Select the Edit button to the left of Tax Matters Contact's name.
Select the Client Centre Access tab and make sure that the
Client Centre Access
toggle button is switched to On and that the contact has registered.