There are many ways to communicate visually and so is the way we adapted a symbol to be used as a logo on a company. A number of popular logos has proven it already, and you might also already know who they are. These logo is a success! Suppose you want to deliver a message about food product through a logo, so you do not have to describe it with a symbol of people who are devouring the food. Similarly, when you have a headache that does not mean your head physically sick, it could have occurred because of thinking about lovers that never reply to sms. :D
Xerox logo is not a symbol of a photocopier, fedex logo is also not a symbol of a courier, amazon logo is not even related to the forest, or if you love nature does not mean you have to hug a tree or kissing it.
Logo about computer does not have to show a computer image so it looks like the synergy with the technology, coffee shop or café logo does not have to be a glass of warm coffee symbol, barber shop logo also does not have to be a scissors symbol, logo of traveling does not have to be a car symbol , drug store logo design does not need to show the drug.
Just because it is considered relevant, it does not mean you can not do better by using an alternative design that does not describe the product or service offered by your clients. Basically, you will present your logo design to clients, and make them believe that your design is correct, and appropriate is a proof that you're logo is communicating.
If you are unable to convince your client, that does not mean you are a bad in design, but it could be the way you say what's in your mind about the logo design that has been made , is considered less convincing clients. It could be that you do not understand what the client wants to hear from you (a designer). Change your grammar, give your client enlightenment, subtract your selfishness, think like a client and act as a professional designer. We designers are problem solvers, the source of the solution, they said.