My keyboard on iMessage won't pop up. Just the subject/message line is showing at the bottom. I searched the internet for solutions and tried what was suggested: powering off/on and hard reset (sleep/wake+home). The only thing next to try is backup and restore but that will take a long time. Is there something else I can try first?
I had the same problem. Turns out that my iphone was trying to connect to an Apple bluetooth keyboard. I turned off bluetooth on the iPhone and the keyboard re-appeared immediately. No need for a reset or hard boot.
The solution that worked and is faster than powering off/on was to go to settings/general/keyboard and deleted the 3rd party keyboard I had installed.