Grant permission to sharepoint group

I have created some SharePoint groups and I am using the grant permission action to grant the group members permission to and Item and send them an email

the group name is a combination of a dropdown menu and “Mail” I have added the log action to check if it gets the right name and it does but the workflow suspend when it reaches the granting stage with the following error

Hello May,

According to the log error, it tries to convert the string value to an integer value without success.

Could you please send me a screenshot of the workflow at [email protected].