The screenshot shows eplus, which is the ticketing service used by (basically) all BanG Dream! concerts, specifically the application history page (see also asset #41453562). However, the e-mail shown in the anime somewhat resembles pia, another ticketing service (used by Girls Band Cry concerts actually), as can be seen in asset #41453500. It's obviously far from a perfect match, but at least there's some similarities, unlike the eplus lottery result email (asset #41453503).
Both pia and eplus have the benefit of not being l-tike, which I'm pretty sure is a tool of psychological warfare based on how bad it is to use.
