"Low on storage space" But I have 1.7GB free space
I believe that most phones seem to like a certain amount of space free, to keep things  running smoothly. If you try to downloaded something that would leave too little space free, it won't let you. Kind of like how Apple IOS system updates can required 4GB of free space though it may need less than 1GB in reality.

In any case,  your phone is capable of using a removable microSD card, and with the piddly 4GB of internal storage- of which only 2.5GB are available to the end user, that is exactly what the phone makers are encouraging you to do. You should invest in a microSD they are available in large sizes- 32gb is the largest without needed to format the card.