No listener listening on port 50000 after restart Netweaver CE 7.2

I installed Netweaver CE 7.2 MaxDB on Solaris 10 x64 then deployed ACC on it.

It used to work well until after a restart, there is no listener listening on port 50000.

The url is http://<IP>:50000/, which is not responding.

Because a java component hung, I called "stopsap j2ee" then "startsap j2ee".

But I found there is no listener on port 50000. Then I called "stopsap all", reboot the local zone where sap runs on, "startsap all".

I noticed there is "Unable to open trace file sapstartsrv.log." but don't know if this is the cause. I can not find anything related in SAP notes.

sap4-x64-acc72:c72adm 2% startsap all
Checking ADA db Database
------------------------------
setTrace: false
J2EE Database is not available via  test
See logfile /saphome/c72adm/JdbcCon.log
Running /usr/sap/C72/SYS/exe/run/startj2eedb
Trying to start database ...
Log file: /saphome/c72adm/startj2eedb.log
C72 database started
/usr/sap/C72/SYS/exe/run/startj2eedb completed successfully

Starting Startup Agent sapstartsrv
-----------------------------
Mar 25 21:55:58 sap4-x64-acc72 SAPC72_01[12616]: Unable to open trace file sapstartsrv.log. (Error 11 Resource temporarily unavailable) [ntservsserver.cpp 2645]
OK
Instance Service on host sap4-x64-acc72 started

starting SAP Instance SCS01
------------------------------
Startup-Log is written to /saphome/c72adm/startsap_SCS01.log
/usr/sap/C72/SCS01/exe/sapcontrol -prot NI_HTTP -nr 01 -function Start
Instance on host sap4-x64-acc72 started

Starting Startup Agent sapstartsrv
-----------------------------
Mar 25 21:56:09 sap4-x64-acc72 SAPC72_00[12909]: Unable to open trace file sapstartsrv.log. (Error 11 Resource temporarily unavailable) [ntservsserver.cpp 2645]
OK
Instance Service on host sap4-x64-acc72 started

starting SAP Instance J00
------------------------------
Startup-Log is written to /saphome/c72adm/startsap_J00.log
/usr/sap/C72/J00/exe/sapcontrol -prot NI_HTTP -nr 00 -function Start
Instance on host sap4-x64-acc72 started

sap4-x64-acc72:c72adm 3% netstat -a |grep 50000 
<- no process listening on port 50000

Many Thanks,

Sherry