In Explorer for Institutions, you might see transparent donuts with a question mark in the center, as in the example below. This is indicates a research output without an Altmetric Attention Score that was added to your institutional database during your data implementation. 

Transparent donuts might still have underlying attention data, e.g. Mendeley readers and Scopus citations, that do not contribute to the score. The donut will light up when it gets a score and you can now sign up for email alerts from the details page to monitor future attention.