Hi its me Vanessa :),
i am working on Shopware local with vagrant. Recently i can not login in the Backend i get the following message:
The Symfony Profiler is showing this Message:
I would be very grateful if someone could help me 
Best regards
Vanessa
Did you already check if the APP_URL in you .env file ist correct?
Alternatively you could check if resetting the password as described in this tutorial resolves the issue: https://docs.shopware.com/en/en/shopware-6-en/tutorials-and-faq/reset-admin-password