Samy, Blu Studio 5.5 S smart phone insufficient storage for apps. It sounds like you may have to clear up some space or move apps to SD card.
Check the attached links,instruction and guides, Good luck
I hope this helped you out, if so let me know by pressing the helpful button.
http://www.pcadvisor.co.uk/how-to/google-android/how-fix-androids-insufficient-storage-available-error-message-summary-cache-3623467/
https://www.youtube.com/watch?v=LilzsoSdBNY
http://www.gsmarena.com/blu_studio_5_5-reviews-5761.php