User type "System" - Test

Dear All,

I am not quit sure if this is the right place for my question....

We have in our ERP System one user which is type system.. an external application needs to connect our system using this user..but it is having problems because apparently user / password is wrong..... we do not think the problem is on SAP side ... but we need to prove this.....Is there some way to test that user and password are OK ?

I will appreciate any idea

Thanks.

FedeX