David’s publishing company's main channel of communication is email. As a publisher, they are constantly emailing artists, graphic designers, fulfillment services etc.
The problem was that they received an incredible amount of junk mail, and many of their emails were going undelivered. Undeliverable or rejected emails is a common problem with using companies like BlueHost and HostGator for your emails. For David's company, this was unacceptable. Deadlines were being missed, clients getting frustrated etc.