The phone has insufficient memory. Storage space is full. Unable to access text messages.

Insufficient phone memory does not refer to the memory card, but to the built-in memory on the phone. Generally, it is shown as the C drive. Install a manager to check if there are any unused software in the built-in memory of your phone and delete it. Also, try not to play around with the installation software and choose the C drive. Generally, the C drive does not have a lot of memory.