Substitution mode RECEIVE_TASKS not supported for provider in Fiori Inbox
We have implemented Fiori Inbox functionality for Substitution option (Client doesn't have Portal to maintain substitutes and don't access SAP R/3).
In the Inbox, I selected 'Manage My Substitutes' option on the top right corner. I selected 'Add New Substitute', entered the substitute, selected 'Task Group' as 'All' and selected the validity period.
When I click on 'Save' button I'm getting an error 'Substitution mode RECEIVE_TASKS not supported for provider'.
Can you please guide me what I have to do at the backend to resolve this error. Any help on this is greatly appreciated.