As Sister Momo has said, a majority of the problems with this quest step come from keyboard or typing settings on your device.
If you auto-complete the phrase from a suggestion (because you had it typed before), there will usually be a space added automatically after the inserted phrase.
However the quest counter is very sensitive, and will not count if you had an additional space.
You should check out the quest counter after you entered the word and made sure no additional space was added. If you still experience the issue, let us know here in the thread.