A transaction is currently not possible. What does that mean?
For a long time I have been trying to order via online banking with Klarna but every time I have filled out everything it says this transaction is not possible why is that I absolutely need clothes
You cannot run the transaction (i.e. this payment process) in this way at the moment.
Unfortunately, we cannot tell you from a distance and only on the basis of the information provided by you in the question.
If there was no reason in the message, we know it even less than you. Because we do not know the exact circumstances in which the message occurs with you, nor do we know the internal mechanisms of Klarna which lead to the relevant message exactly with you and at the moment.
Then go to a store and buy it there or order it and pay it directly (without using services like Klarna).