Browser Issues
The ROS digital cert must be loaded into the browser before the process will work.
Here are some instructions on how to do that
Please ensure you use the same browser to login to CORE as you do for Revenue/ROS.



The CRO requires 3rd party cookies to be enabled as ROS is a 3rd party to CORE.
Certain Browsers work and others do not.

  • ● Chrome works most of the time.
  • ● Firefox works most of the time
  • ● No reported issues with Microsoft Edge
  • ● Safari does not work at all, but Chrome does work on a MAC (usually).


To sign on CORE you must have an active ROS sub-user certificate issued in the name of the CORE signatory.
The certificate must be issued from the tax registration number or TAIN designated as the signer in CORE.  (otherwise, you get the below message)



This means that if you want to sign company accounts as a Director, you must have a sub-cert issued by that company’s ROS Administrator.  If you are an Agent, you must have a sub-cert issued by the EFA ROS Administrator – this may be a Revenue TAIN or a tax registration number.

EFA must have a sub-cert issued in the name of the Agent as recorded with CRO.  The Agent name comes up as the signatory.
The CORE system should show the name of the expected signatory and whether the signer is and EFA (electronic filing agent) or a Director/Secretary.
EFA’s must be approved by CRO to file on behalf of clients.
Example of where information may be viewed on CORE for BI form.


If the name of who the sub-cert was issued to does not exactly match the name of the signatory on CRO, or if the sub-cert was not issued from the correct ROS account this type of error can occur:



Other errors may relate to the ROS sub-user certificate.  Certificates may become:

  • ● Expired – ROS certs must be renewed at least every two years, or they expire and become invalid
  • ● Suspended – if the ROS Administrator certificate expires, all sub-user certificates are suspended and are invalid until the ROS Administrator certificate is restored.
  • ● Revoked – if the sub-user certificate is renewed, the previous version of the certificate becomes invalid.  This can be a problem if the certificate is being shared.  If one user renews the certificate, all copies of the previous version become invalid.

    The ROS Administrator may suspend or revoke a sub-user certificate at any time.
    Below is the type of message which may occur:


Here is some information from Revenue on signing with ROS,

This link is instructions to register with ROS:

Instructions from the Revenue Site on how to create a sub user ROS Cert can be found at

You must save your ROS cert to your computer. Here are some instructions on how to do that.

You will need to load your Digital Signing Cert into your browser. Here are some instructions on how to do that .

Please ensure you use the same browser to login to CORE as you do for Revenue/ROS.If you have issues with ROS, please follow this link.

ROS Help Centre: