Hello Vladimir,
Does your database logon issue occur if you use that connection string in any application other than TestComplete? To check whether the issue is caused by TestComplete's ADO object's incorrect behavior, you can create a simple Delphi or Visual C++ application connecting to your database using the same connection string you are using in TestComplete.
Still, to help us investigate the issue, could you please use this web form to contact our Support Team and send us your problematic TestComplete project, your tested application or web site and the credentials required to log in to your database?
Thanks in advance.