Grammarly is utter garbage. It's touted as a software for 'writers' - it is actually a software to teach people how 'not to write'. You see that sentence I just wrote? Grammarly would find fault with it, telling me that it was 'difficult to read'. Yes, it is indeed difficult to read - if you assume that the human race all have the average intellectual power and reading capabilities of a $#*!ed chimpanzee! If you listen to Grammarly's suggestions, you will lose all sophistication in your writing, and sound as if you were writing for kindergarten children - or those said chimpanzees.
There's no need to underestimate the human race - remember that in $#*!ens' time, even the man on the street could understand and appreciate his works. $#*!ens, Thackeray - take any or all of the great writers, the MASTERS of the English language - and Grammarly would find fault with almost every sentence they wrote.
Grammarly should stop putting their silly, stupid advertisements up all over the net. If any of them survive into the future, archaeologists will use them as evidence that humanity in this age, and taken as a whole, were almost illiterate - and perhaps even regressing in terms of evolution back to the chimpanzees I mentioned earlier.
And that was a message written without the aid of Grammarly.