The planet Mercury went retrograde on the 26th of July. Now in astrology it means, when the planet Mercury changes directions, reverses course, etc. (A planet can't reverse course, it only orbits the Sun in one direction. But, it can appear that way.) Astrology believes it becomes responsible, like Murphy's law (everything that can go wrong will go wrong), for everything. They say don't sign contracts, mechanical things go wrong, messages get misinterpreted and so on. Below you have Mercury Retrograde explained without Astrology.
Now, for fun, explained WITH Astrology. And remember this one is on a blood full moon with the longest eclipse of the last 100 years! Be careful!