3487967 - Error while publishing payload to endpoint. Status code : 531 - Onboarding

• Customer implemented IAS and doing Real time sync for new hires, after user creation in ONB. New hires are not showing in IPS. 
• Error while publishing payload to endpoint. Business Key : eb408046-55d7-422d-b2e2-3213e61a4257 Status code : 531

SAP SuccessFactors Onboarding

In Execution Manage Dashboard

1. Go to SuccessFactors Instance
2. In the Admin Center, search Execution Manager 
3. Select Pre-delivered integrations
4. Check the date range for Real-time Sync
5. Check if the Process State is 'Completed with errors'. 
6. Check Error, getting error 531. (Sample error below). 

Error while publishing payload to endpoint. Business Key : eb408046-55d7-422d-b2e2-3213e61a4257 Status code : 531

There is an invalid character in the email ID (capital letter, hyphen '-' or dash '_', or any other special character like '?')

Maintain email IDs that only consist of lower-case letters ('a' to 'z') or digits ('0' to '9')

Real time sync, Status code : 531, special characters , KBA , LOD-SF-OBX-IAS , IAS User Authentication , Problem