A lot of people use Gmail but don’t realise the limitations of the service.
In this case I emailed a client a zipped file which contains an executable program. Google could easily scan attachments to make sure the attachment doesn’t contain a known virus, but they’ve made the decision to simply stop all such emails.
There are a number of solutions to get around this issue to trick Google, but each requires work that isn’t necessary. Because of the time involved I now simply refund the client’s money and they miss out on the solution to their needs and I miss out on the sale. In time because of the work involved prices will most likely be increased to cover the additional workload created by services like Gmail. Unfortunately the extra time and effort caused by Google means it isn’t worth the time for the low value of the sale.
If you’re thinking about using Google’s Gmail service get to know its limitations. For business I would not normally recommend Gmail as an email service. Google isn’t the only service to make such decisions on the behalf of their users. I find those services that make too many decisions on behalf of users tend to damage the users experience, often without the users knowledge.