XPRESS Licensing Error (Error nv01) on Server Environment – Single Use Class 2

[StatNI]

Hello everyone,
we recently received the XPRESS Solver and set it up following FICO's instructions. After some initial unsuccessful attempts, we were at least able to run two error-free instances using version 3.5.0 Build 27. Higher versions crashed immediately with an error message. In the meantime, we are now also receiving an error in version 3.5 – despite using the same data and inputs as in the two successful runs.
The error messages in detail:

3.5.0:
Xpress licensing error 9: The host ID of this machine could not be detected. Please contact the Xpress support team. (Error nv01)

4.2.5 Build 2:
JJ-routines: XPress license error
libTauHiTaS version is 4.3.2.1
Using XPRESS
Exited with code 8000: JJ-routines: XPress license error

Regarding our setup: We are running the solver in a server environment (no local installation), configured as Single Use – Class 2 for multiple users. All errors occur on the same server. Nothing has changed in the configuration between the successful and the failed runs.
Particularly notable regarding error nv01: The host ID reported by the system is identical to the host ID we submitted to FICO during licensing – so there does not appear to be a discrepancy at that level.

Troubleshooting steps we have already taken:

• Tested with input data from a colleague's office that had previously run successfully with XPRESS – also without success

• Replaced the DLL files xprl.dll and xprs.dll as described in several forum posts – unfortunately also without success

What puzzles us most is that version 3.5 worked temporarily, without any apparent explanation for the subsequent failure.
Does anyone have an idea or a possible solution?

Thank you very much!

[ppdewolf]

When you get the error in 4.2.5, do you have a XPerror.log file in your %TEMP% directory? That might contain some clue on the reason for the XPress license error.

[StatNI]

Thank you for your quick response. With version 3.5.0, the XPerror.log file contains the error already mentioned above: Xpress licensing error 9: The host ID of this machine could not be detected. Please contact the Xpress support team. (Error nv01)
With version 4.2.5, the file is empty.

[StatNI]

Hi @ppdewolf , just a gentle ping on this — wanted to make sure my last update didn't get lost. Let me know if you need any additional info from my side. Thanks again for taking a look!

[ppdewolf]

Going on the information you've provided, there are a few things I can mention:

• I don't think the error/crash occurs because of the input data. However, to be sure: did you try the example data (tau_testW.asc) that come along with the zip-file?
• The zip-file with the 32-bit Windows version of tau-argus has the xprs.dll and xprl.dll that are used. If you replace them by other dlls (newer versions, 64bit perhaps) I do not know what will happen.
• The message about the host ID suggests that there is something wrong there. Do you have an xpauth.xpr file located in the directory where the tauargus.exe is located?
• Because of the host ID error I would suggest to contact FICO as well.
• Are you using XPRESS for anything else except tau-argus? If so, does the license work for those situations?

[StatNI]

Thank you for your reply. We tried a run with the sample dataset tau_testW.asc, unfortunately with the same error message. We then replaced the .dll files with the 64-bit version. Indeed, we no longer receive a "JJ-routines: XPress license error" with either our data or the sample dataset, but instead an "Error in modular suppression procedure". The log file with our data looks as follows:

29-Apr-2026 13:02:45 : Tables have been read
29-Apr-2026 13:02:45 : Xpress
29-Apr-2026 13:02:45 : MOD(1,2,1,1,0)
29-Apr-2026 13:02:45 : Start of the modular protection for table a_1 x reg x wz | x1
29-Apr-2026 13:02:45 : Error in modular suppression procedure

29-Apr-2026 13:02:46 : (1,2,AS+,"D:\TauArgus\TauArgus-SW\Test2\test.csv")
29-Apr-2026 13:02:46 : Table: a_1 x reg x wz | x1 has been written
Output file name: D:\TauArgus\TauArgus-SW\Test2\test.csv

When switching to the 32-bit version, we receive the following error: "XPRESS error: Xpress licensing error 89: Your license only supports platform(s) win_x86_64, linux_x86_64, linux_aarch64. Please contact support@fico.com to upgrade it."

[ppdewolf]

Since tau-argus (as distributed as binary) itself is a 32bit application, I suggest to use the xprs.dll and xprl.dll that are included in the zip-file, as they should be consistent with the use in tau-argus. Newer versions might have a slightly different API what potentially could lead to crashed (the "old" function call might not be correct or even not available at all when using the "new" dll).

I am a bit confused by your comment. At the end you mention "switching to the 32 bit version". Do you mean the dlls that are included in the zip-file? In your first message you mentioned a different error message, but (as far as I understand your messages) with the same dlls?

The error number 89 suggests that you have a license for 64bit only, whereas tau-argus is currently still 32 bit. In that case you have to contact FICO and ask for a license that also allows 32 bit versions of Xpress.

So please tell me exactly:

• On what platform is tau-argus running? Windows, Linux, 32bit, 64bit, ...
• Do you have xpauth.xpr located in the directory where tauargus.exe is located?
• What xprl.dll and xprs.dll are located in the directory where tauargus.exe is located? They should bev 32 bit with:
  • xprs.dll: file version 28.1.4.0 / product version 28.01.04
  • xprl.dll: file version 2.7.7.0 / product version x7.9
• When you run the command "file x*.dll" in the directory where these dlls are located, do you get something like this:
  • xprl.dll: PE32 executable for MS Windows (DLL) (GUI) Intel 80386 32-bit
  • xprs.dll: PE32 executable for MS Windows (DLL) (GUI) Intel 80386 32-bit

[StatNI]

Hello,
sorry for the confusion. We had some internal communication issues that I would like to clear up.
What I referred to as the 64-bit version in my previous post were actually different 32-bit versions, which led to different error messages in the respective log files:

TauArgus 4.2.5
• With original DLLs (xprs 28.1.4.0, xprl 2.7.7.0):
o Logbook: Error in modular suppression procedure JJ-routines: XPress license error
o XPress.log: XPRESS error: Xpress licensing error 89: Your license only supports platform(s) win_x86_64, linux_x86_64, linux_aarch64. Please contact support@fico.com to upgrade it.
• With DLLs from the 32bitdlls folder on GitHub (xprs 23.1.6.0, xprl 2.6.5.0):
o Logbook: Error in modular suppression procedure
o XPress.log: No XPress.log file is generated.

Here is the additional information you requested:

On what platform is tau-argus running? Windows Server 2022, 64-bit.
Do you have xpauth.xpr located in the directory where tauargus.exe is located? Yes, the file is located in the TauArgus folder, in the same directory as tauargus.exe.
What xprl.dll and xprs.dll are located in the directory where tauargus.exe is located? As described above.
When you run the command file x*.dll in the directory where these dlls are located, do you get something like this?
• xprl.dll: PE32 executable for MS Windows (DLL) (GUI) Intel 80386 32-bit
o Output: 32-bit (PE32)
• xprs.dll: PE32 executable for MS Windows (DLL) (GUI) Intel 80386 32-bit
o Output: 32-bit (PE32)

We are now assuming that we received a 64-bit-only license from FICO and therefore need to ask them again for a 32-bit version.
Once again, sorry for the misunderstanding – I hope this is clearer now.