SIgnature issue in custom App

I am trying to build a custom app for my WD My Cloud Mirror, but I have some pb.

I followed this topic My Cloud OS5 App Template, and build the package with mksapkg. On my WD My Cloud Mirror, I have the following error message when I try to install the package with upload_apkg :

$ upload_apkg -d -t 2 -p WDMyCloudMirror_CustomApp.bin

[upload_apkg.c:917] [/mnt/HD/HD_a2/Nas_Prog/_install/CustomApp/apkg.sign]
[upload_apkg.c:918] [0]
[upload_apkg.c:922] signature failed2 [CustomApp]
[upload_apkg.c:248] log : analyticlog -l INFO -s upload_apkg -m analytic_info string:appName:“NA” string:status:“instFail” string:error:“uploadAppFail”

During the build of the package with mksapkg, I got some warnings, but I don’t know if they are related with this signature :
*** WARNING : deprecated key derivation used.
Using -iter or -pbkdf2 would be better.

The openssl version used on the linux box is “OpenSSL 1.1.1w 11 Sep 2023”, maybe that explain the warning.

If someone has an idea…