Tell us in breif about the error, since when did you start facing it? what device are you on? Right now i can only assume is that you are using a older lumia device with windows phone 8.1
to begin the troubleshoot, i would you to make sure that location; find my phone, backup, Wi-Fi are turn on.
Also make sure that in time+data settings automatically settings are turn off and your phone is set up on right region. Then reboot your phone.
The main reasons for this issue involves interruption of the data connection and running out of storage space .