SBS 2011 not sending emails

I have an SBS 2011 not sending emails. I had other issues this morning with an open question here

Now none of the emails are going out. In the Exchange Management Console queue viewer I have this error "451 4.4.0 DNS query failed". It keeps on retrying but no luck.

I use the ISP SMTP server for sending emails. I can telnet the SMTP server no problem. It does not appear to be an DNS issue.
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GerhardpetAuthor Commented:
GerhardpetAuthor Commented:
Issue solved with a reboot of the server. Not sure what the problem was.

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