“Fatal NI Connect Error 12516″ and ”TNS-12564: TNS:connection refused” In Clusterware Alert.log when ologgerd Connects to GIMR

Fatal NI connect error 12516, connecting to:
(DESCRIPTION=(CONNECT_TIMEOUT=60)(ADDRESS=(PROTOCOL=tcp)(HOST=racnode-cluster-scan.virtuallab)(PORT=1521))(CONNECT_DATA=(SERVICE_NAME=GIMR_DSCREP_10)(CID=(PROGRAM=ologgerd)(HOST=racnode1.virtuallab)(USER=root)))(SECURITY=(ENCRYPTION_CLIENT=requested)))
VERSION INFORMATION:
TNS for Linux: Version 19.0.0.0.0 - Production
TCP/IP NT Protocol Adapter for Linux: Version 19.0.0.0.0 - Production

Version 19.8.0.0.0
Time: 08-AUG-2020 18:15:01
Tracing not turned on.
Tns error struct:
ns main err code: 12564

TNS-12564: TNS:connection refused
ns secondary err code: 12560
nt main err code: 524

TNS-00524: Current operation is still in progress
nt secondary err code: 115
nt OS err code: 0

INVESTIGATION

Check mgmtlsnr or SCAN listeners, and found -MGMTDB PDB service ” gimr_dscrep_10″ is not registered properly.

[grid@racnode1 trace]$ lsnrctl services listener_scan2
...
..
.
Service "gimr_dscrep_10" has 1 instance(s).
Instance "-MGMTDB", status READY, has 1 handler(s) for this service…
Handler(s):
"DEDICATED" established:0 refused:0 state:blocked
REMOTE SERVER
(ADDRESS=(PROTOCOL=TCP)(HOST=172.16.100.62)(PORT=1526))