Shared web space limit warning but zero articles inside

Hello I have created a Group to share references with my supervisor. As we began we had a lot of articles to share so we quickly reached the web space limit which led to the yellow ribbon with the warning "You have reached your Shared Web Space limit" but since then we each moved the articles to our own libraries and I emptied this group. It now has zero articles but the same warning still appears. What could be the issue? Thank you