Credentials issue with MS SQL Express 2014

Question

Hello,
I have kind of simple issue but I failed to resolve it. Here's the issue:
I have SQL Server Express 2014 installed on my PC. I have to use SQL Server authentication. As 'sa' I created login and user e.g. user1. Then as user1 I created DB e.g. db1 and a few tables. Now I could login into db1 as user1 using SQL Server authentication.
This db1 will be used by application e.g. app1. This app1 has configuration file that has all credentials and other connection string things. Well when I start that application it throws error "Can't connect to database". Then I look into log and
see this: Error: 18456, Severity: 14, State: 8. Login failed for user 'user1'. Reason: Password did not match that for the login provided .  Then I could disable credential check in configuration file of app1 and then I don't have problem to start app1.
Then I tried to created ODBC connection and use the same credentials and I succeed to connect. Could some give the idea what could be wrong and I can't connect to db1 from my app1? Thanks

Answer 1

Reset the password of the login, i have already this problem.
Not forget the connection string syntaxe, do not make the space after and before (=) example :
Server=myServerAddress;Database=myDataBase;User
Id=myUsername;
Password=myPassword;
Thanks for suggestion ... but could you please tell me why  to reset login password ( I could use this password successfully when login from Studio i.e. it's correct.
Could you please give me sqlcmd example how to connect to my db1 using connection string. That way I should be able to check which users are capable to login.
N.B. I am planning to play with Trusted Connection because Shanky_621 suggested that value 'false' (like in my case means Windows Authentication). In my case user1 is not Windows user .. it's SQL Authentication user.
Thanks