Cannot get ntpdate cron to run
Ensure you have a shebang "#!/bin/bash" to specify howthe script is to be parsed.
ntpdate script:
#!/bin/bash
/usr/sbin/ntpdate ntp.ubuntu.com pool.ntp.org
As an alternative to using cron, you could just install ntp
and let the daemon automatically adjust the clock for you while the server is running.