The SeriviceNow user needs 3 roles in ServiceNow for the sdgtw probe to work as expected:
In general, the personalize_dictionary roe has read, write, create, and delete permissions on the sys_dictionary table.
The sdgtw probe needs roles with read-only access on the sys_dictionary table for the ServiceNow user.
This lets the user create a separate ACL role with read-only access to the sys_dictionary table. You can provide this role to the ServiceNow user configured in the probe"
As per probe documentation, for ServiceNow, it is required the role personalize_dictionary for the connection profile. This role (as far as I know) has access to next tables
As an alternative the documentation mention that you can create a role with same accesses as personalize_dictionary, but with read-only access to sys_dictionary table.