When experiencing database problems, most often manifested by an outbound dialing issue or a time syncronization issue, try running the following command from your SSH client:
mysqlcheck -u cron -p 1234 --auto-repair --check --optimize --all-databasesYou can also use the root MySQL credentials. Make sure to restart the asterisk service just in case:
service asterisk restartor
pkill -9 asterisk asterisk -vgc