Freeradius failed to update database TXT_DB error number 2

Certificate is to be certified until Dec 11 20:03:46 2019 GMT (60 days)
failed to update database
TXT_DB error number 2
make: *** [server.crt] Error 1

TXT_DB error number 2 failed to update database

Problem:
Because you have generated your own self signed certificate with the same CN (Common Name) information that the CA certificate that you’ve generated before.