2897521 - SQL6048N and SQL1032N reported on Db2 database startup.

You've made no changes to the Db2 database environment.  But a during a regularly scheduled database restart you see the following sql errors reported and the database won't start.

db2start
02/26/2020 15:57:21 0 0 SQL6048N A communication error occurred during START or STOP DATABASE MANAGER processing.
SQL1032N No start database manager command was issued. SQLSTATE=57019

The db2diag.log shows the same sql errors with with no useful information as to what's causing the error:

2020-02-26-16.13.37.499843-180 I3550A1192 LEVEL: Event
PID : 16580972 TID : 1 PROC : db2start
INSTANCE: db2sap NODE : 000
HOSTNAME: ERPFIPRD
EDUID : 1
FUNCTION: DB2 UDB, base sys utilities, sqlePrintFinalMessage, probe:13549
DATA #1 : unsigned integer, 4 bytes
0
DATA #2 : signed integer, 4 bytes
1
DATA #3 : SQLCA, PD_DB2_TYPE_SQLCA, 136 bytes
sqlcaid : SQLCA sqlcabc: 136 sqlcode: -6048 sqlerrml: 0
sqlerrmc:
sqlerrp : SQLEOCON
sqlerrd : (1) 0x00000000 (2) 0x00000000 (3) 0x00000000
(4) 0x00000000 (5) 0x00000000 (6) 0x00000000
sqlwarn : (1) (2) (3) (4) (5) (6)
(7) (8) (9) (10) (11)
sqlstate:
DATA #4 : SQLCA, PD_DB2_TYPE_SQLCA, 136 bytes
sqlcaid : SQLCA sqlcabc: 136 sqlcode: -1032 sqlerrml: 0
sqlerrmc:
sqlerrp : SQL11014
sqlerrd : (1) 0x00000000 (2) 0x00000000 (3) 0x00000000
(4) 0x00000000 (5) 0x00000000 (6) 0x00000000
sqlwarn : (1) (2) (3) (4) (5) (6)
(7) (8) (9) (10) (11)
sqlstate:

The database directory listing looks correct:

db2 list db directory
System Database Directory
Number of entries in the directory = 1
Database 1 entry:
Database alias = SAP
Database name = SAP
Local database directory = /db2/SAP
Database release level = 14.00
Comment = SAP database SAP
Directory entry type = Indirect
Catalog database partition number = 0
Alternate server hostname =
Alternate server port number =

With errors SQL6048N and SQL1032N pointing to an issue with the Db2 node you attempt to catalog the database, but the database is not found:

db2 catalog database SAP on /db2/SAP
SQL6028N Catalog database failed because database "SAP" was not found in the local database directory.

Db2 LUW (DB6) all versions.

db2stop restart , KBA , BC-DB-DB6 , DB2 Universal Database for Unix / NT , Problem