I got this error message on 19c dataguard production database at alertlog.

The primary alert log file showed:

LGWR: Attempting destination LOG_ARCHIVE_DEST_2 network reconnect (16198)
LGWR: Destination LOG_ARCHIVE_DEST_2 network reconnect abandoned

Fri Apr 3 02:00:36 2022
Errors in file //bdump/.trc:
ORA-16198: Timeout incurred on internal channel during remote archival
LGWR: Network asynch I/O wait error 16198 log 2 service ‘(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=)(INSTANCE_NAME=)(SERVER=dedicated)))’

After investigate issue we noticed that our network is too slow. We got this error if primary try to send big logfile to standby database.

At the primary database NET_TIMEOUT attribute in the LOG_ARCHIVE_DEST_2 not set or set to low value(such as 5-10) than LNS couldn’t finish sending redo block in xx second.

You’ll need to increase the NET_TIMEOUT value in the LOG_ARCHIVE_DEST_2 on the primary to at least 15 to 20 seconds depends on your network speed.

In our case we set it to 120.

ALTER SYSTEM SET LOG_ARCHIVE_DEST_2 SERVICE= LGWR SYNC DB_UNIQUE_NAME= NET_TIMEOUT=60 VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE)

Reference:
Redo Transport Services fails with ORA-16198 when using SYNC (synchronous) mode (Doc ID 808469.1)