Hey EnRo1337,
Follow the steps below: 1) Launch Multi Theft Auto 2) Join a server 3) Download https://qais.jp/mta/diag and open MTADiag 4) Wait till it's completed and it will add a link to your clipboard 5) Paste the link you get in here so we could look into it.
Keep in mind, if you need any help in the future, follow these steps because we need as much information as possible to be able to help you.