Hey Emma 🌸 The blue/green shift that is seen in the hair after using Wella Color Fresh Mask in the shade Cool Espresso is probably due to the hair being too light or porous in certain areas before application.
What are you doing now, because I understand that you want to get rid of this as soon as possible.
A clarifying shampoo can help draw out excess pigments.
Mild warm color treatments (like beige or light gold tones) can help neutralize the blue-green without making the hair orange.
Avoid cool color masks until the tone is balanced.
As mentioned below, get help from our hairdressers, ask and consult, they are the best 🙋♀️😍