SAP FIORI MyInbox authorization error while adding Substitues

Hi All,

When I was trying to create a substitute rule for other users I am getting an authroization issue but I am not sure what role I am missing here.

The workflow source from SRM and ECC systems .

Steps to reproduce:

1. Logon MyInbox

2. Manage Substitutes

3. Add New substitute Rule

4. I selected the user , profile and add , here I am getting an error as below:

The logs says authorization error but I am not sure what rule this user needs to be assigned?

The below are the roles assigned in Gateay:

/IWPGW/RT_WF_USR

ZSAP_FND_BCR_MANAGER_T

ZSAP_FND_TCT_T

Z_SAP_S_RFCACL

SInce the work items are pulled from Backend is there any special getway roles do I need to provide?

Thanks

Krishna