I used UaCtt-1.3.341.396-x86_64.AppImage, the following happens:

Session Base/008.js
Error: Test.Execute() encounted an unexpected error:
message:buildUserNameIdentityToken(session = UaSessionClass(name = ""), username = 'User1', password = 'Pwd1', doNotAppendNonce
= false) at /home/ed/OPCToolboxV5/EmbeddedStack/Source/CTT/EmbeddedCtt/library/Base/identity.js:327
lineNumber:327
sourceId:140453729248576
fileName:/home/ed/OPCToolboxV5/EmbeddedStack/Source/CTT/EmbeddedCtt/library/Base/identity.js
name:TypeError

Backtrace: function:
file: .../library/Base/safeInvoke.js
line: 126
file: .../maintree/Session Services/Session Base/Test Cases/008.js
line: 39

I debugged a bit, and the last thing before the script crashes is here:
Base/identity.js line 326:
var status = cryptoProvider.asymmetricEncrypt( encodedPassword, gServerCapabilities.ServerCertificate.PublicKey, encryptedPassword );

this line jumps directly to the exception handler.