From 20th March 2020, MyGovID and Relationship Authorisation Manager (RAM) will replace AUSkey as the secure login for government online services.
Use this link and follow the steps to set up your MyGovID and link your business via the Relationship Authorisation Manager (RAM) https://www.mygovid.gov.au/how-do-i-get-set-up
Some additional links –
For further queries or problems, call the MyGovID helpline on 1300 287 539 (option 3)and the ATO will be able to check eligibility and link the business manually.
*Please note that all Discretionary Trusts currently need to be linked manually via the MyGovID helpline on 1300 287 539 (option 3)