ERRORS: "XCOMM0780E Txpi 226 ..." and "XCOMM0780E Txpi 215 ..." XCOM For Windows

Products

• XCOM Data Transport
• XCOM Data Transport - Windows
• XCOM Data Transport - z/OS

Issue/Introduction

We have transfers issues between a newly created Windows XCOM for Windows 11.6 SP03 instance and Mainframe. 
We get different errors on each attempts and occasionally the transfer works successfully.
Errors we've seen so far: 

XCOMM0785I STARTING TCP/IP CONNECTION TO PORT=08044, IP=xxx.xxx.xxx.xxx   
XCOMM0786I TCP/IP CONNECTION ESTABLISHED WITH DEST=**NONE**, PORT=08044,
            IP=xxx.xxx.xxx.xxx                                            
XCOMM0402I REQUEST NUMBER 002000 ASSIGNED TO TRANSFER REQUEST          
XCOMM0780E Txpi  226: Select timed out with no data available          
XCOMM0783E CONFIRM  REQUEST ENDED DUE TO TCP/IP ERROR                  
XCOMM1168I PLEXQ LISTENER TASK STOPPING                                
XCOMM0071I XCOMJOB NOW TERMINATING                                     

XCOMM0785I STARTING TCP/IP CONNECTION TO PORT=08044, IP=xxx.xxx.xxx.xxx    
XCOMM0786I TCP/IP CONNECTION ESTABLISHED WITH DEST=**NONE**, PORT=08044,
            IP=xxx.xxx.xxx.xxx                                              
XCOMM0402I REQUEST NUMBER 002000 ASSIGNED TO TRANSFER REQUEST           
XCOMM0780E Txpi  215: Socket send error return value = 1127             
XCOMM0783E FLUSH    REQUEST ENDED DUE TO TCP/IP ERROR                   
XCOMM1168I PLEXQ LISTENER TASK STOPPING                                 

And sometimes:
XCOMN0287E Error setting remote user id

One thing we observed is, when the transfers complete successfully, the PORT 8044 on Windows is not released (still shows ESTABLISHED) and then the subsequent transfer attempts fail. 

Environment

• XCOM™ Data Transport® for z/OS
• XCOM™ Data Transport® for Windows

Resolution

The XCOM for Windows listener process caxcgsvr.exe should start an xcomtcp.exe process for each file transfer request that is received.

1. Stopped the XCOM service and also made sure the listener process caxcgsvr.exe was not running.
   Trying to install a patch SO14039 CAXCGSVR PROCESS ENDS SPORADICALLY (enhances listener logging to xcom.log when it fails to create an xcomtcp process successfully) also encountered the error:
   "An error occured while copying one or more of the CA XCOM Data Transport system files. Please refer to C:\Users\USERNAME\AppData\Local\Temp\4\xcompatchinstaller.log for details on the error(s). Maintenance installation will be terminated, correct the error and re-run the maintenance installation."
   The xcompatchinstaller.log file showed 2 messages:
   ===
   Line #26:cmd /c copy "E:\CA\XCOM\Maint64\Patch\\caxcgsvr.exe" "E:\CA\XCOM\\caxcgsvr.exe" /y
           0 file(s) copied.
   The process cannot access the file because it is being used by another process.
   ..
   Line #26:cmd /c copy "E:\CA\XCOM\Maint64\Work\\caxcgsvr.exe" "E:\CA\XCOM\\caxcgsvr.exe" /y
           0 file(s) copied.
   The process cannot access the file because it is being used by another process.
   ===
   Based on the above observations, it appears that the caxcgsvr.exe process is being locked by some other application. 
2. Uninstalled XCOM from the Control Panel (Programs) and it disappeared from there.
   However, the XCOM service was still lingering and the caxcgsvr.exe file was not deleted from %XCOM_HOME%.
   When attempting to delete caxcgsvr.exe by hand, it complained that it was open by “DHCP Client, so stopped that service and tried to delete again, but this time it complained that the “Windows Event Log” had it open, so stopped that service too.
   After that was able to delete the caxcgsvr.exe file and install XCOM 11.6 SP3 back.
   Performed some loop-back transfers successfully after base install.
   Proceeded to apply patch SO14039 CAXCGSVR PROCESS ENDS SPORADICALLY which failed like before,
   Stopped “Windows Event Log” and “DHCP Client” services and re-applied the patch and this time it was successful.
   Subsequent transfer attempts still showed intermittent problems with the listener process caxcgsvr.exe being locked by “Windows Event Log” service.
3. XCOM Engineering's analysis was that something from the operating system (DHCP Client and Windows Event Log services) was holding on to the listener process caxcgsvr.exe. They have not found any evidence that a problem in XCOM would lead to that situation. Their recommendation was to open a call with Microsoft to investigate the symptoms further. 
   It was decided to reimage the Windows Server 2016 Operating System, after which the XCOM installation and subsequent operation was successful.