3575234 - DB6: Password validation fails with "crypt() returned NULL"

System can not start up due to connect user password issue.

db2diag.log:

2024-12-29-09.10.35.935148+000 I99200795E459         LEVEL: Error
PID     : 2646768              TID : 140736603350784 PROC : db2ckpwd 0
INSTANCE: db2abc               NODE : 000
HOSTNAME: abc123
EDUID   : 2                    EDUNAME: db2wdog 0 [db2abc]
FUNCTION: DB2 UDB, oper system services, sqlo_validate_pwd, probe:99
MESSAGE : crypt() returned NULL
DATA #1 : Hexdump, 4 bytes
0x00007FFFCB3D038C : 1600 0000                                  ....

2024-12-29-09.10.35.935302+000 I99201255E470         LEVEL: Warning
PID     : 2646760              TID : 140715212400384 PROC : db2sysc 0
INSTANCE: db2abc               NODE : 000            DB   : ABC
APPHDL  : 0-25587
HOSTNAME: abc123
EDUID   : 189                  EDUNAME: db2agent (ABC) 0
FUNCTION: DB2 UDB, bsu security, sqlexLogPluginMessage, probe:20
DATA #1 : String with size, 67 bytes
Password validation for user <connect user> failed with rc = -2029059891

Direct logon to operating system with connect user returns warning message:
Could not chdir to home directory /home/<connect user>: Permission denied

• SAP on IBM Db2 for Linux, Unix and Windows
• Linux server

crypt(), returned NULL, -2029059891,  , KBA , BC-DB-DB6 , DB2 Universal Database for Unix / NT , BC-DB-DB6-DBA , Database Administration , Problem