We are moving from Powerbuilder 2017 R3 to Powerbuilder 2019 R2. Of 18 client computers where the updated application has been migrated, 17 have reported no issues, 1 can launch the application but gets error when interacting with the database (SQL Server 2019 15.0.4083.2). The error is "Error loading client library DLLs. Unable to connect to server." Based on our error handling arose after executing "CONNECT Using SQLCA;" which resulted in "SQLCA.SQLCODE = -1" and "SQLCA.SQLDBCode" having value other than -103 (for which we believe the error to be an incorrect SQLCA.LogId or SQLCA.LogPass). As part of a login window, the OK clicked event begins as follows

string s_achUserID, s_achPassword
string s_achExtra
date s_dttoday
string s_achTime
string s_achComputerName

SetPointer(HourGlass!)

s_achUserID = sle_userid.text
s_achPassword = Trim(sle_pass.text)
s_achExtra = ""

SQLCA.DBMS = "SNC SQL Native Client(OLE DB)"
SQLCA.LogPass = "sql_server_password"
SQLCA.ServerName = "production_server"
SQLCA.LogId = "sql_server_login"
SQLCA.AutoCommit = False

SQLCA.DBParm = "Database='db_name',AppName='ApplicationName',Host='" + s_achuserid + "',Provider='SQLNCLI11'" // SQL Server 2012 and newer

CONNECT Using SQLCA;
If SQLCA.SQLCODE = -1 Then
   If SQLCA.SQLDBCode = -103 Then
      MessageBox("Error","Cannot Connect to Database - Invalid UserID or Password.")
   Else
      MessageBox("Error","Cannot Connect to Database " + SQLCA.SQLERRTEXT)
   End If
   sle_userid.SetFocus()
   Return
End If

As seen in attachment, it appears this error is being captured with SQLCA.SQLERRTEXT displayed to user. Rolling the user with issue back to an application build deployed with Powerbuilder 2017 R3 resolves the issue.