Memory self healing is supported with Xeon processor from 14th generation of PowerEdge server on wards. Looks like the error message is generic is not correct for 13th generation of server. In 14th generation server, self healing messages (Success or fail) will be logged in LifeCycle Log. You can refer below link for more details on self healing and supported servers [URL] 
Here's an LC log message from a PowerEdge R630, BIOS 2.12.1, iDRAC 2.81.81.81:
Memory self-healing on R630?