HP Laserjet 3015 All in One Printer - Memory Full Error

Please follow the below mentioned step by step procedure to resolve the issue.

Press the menu/enter button on the machine
 
Press the arrow mark(>) button once to select Fax functions , and then press menu/enter
 
Press to select Clear saved faxes , and then press menu/enter .
 
Press menu/enter to confirm deletion.

Now the machine will work normal.