Sql-server – Why isn’t sql server using all of the available memory

Try to find the Non-Delivery Report (NDR) for your outgoing email, then follow the troubleshooting steps on this Technet page.

The simplest path would be to try sending the report file to the external address from an internal mailbox which you DO have access to. This should result in an NDR email being sent to the internal mailbox, which will tell you what is going wrong.

Once you have an idea why the delivery is failing from an Exchange mailbox, you'll want to verify that failure code is actually the same when the Reporting Server sends the email. Assuming that your Reporting Server is sending the email out via SMTP directly, you will have to find the NDR in a log somewhere else, since there may be no mailbox to send the NDR to. This page has good information on How to Monitor Exchange NDRs.

I agree with leaving it alone for now. SQL will try to load as much into memory as it can, up to the amount defined in MAX SERVER MEMORY. Your 600MB db will obviously fit into memory in your current config. Your server should have plenty of memory leftover without having to tweak SQL memory settings. Watch it as your database grows, though. (I'm not sure what the velocity of your db growth is)

Something I like to do is set SQL's max memory to (Physical Memory)-1.5GB just in case something in the instance wigs out. That way you still have some memory for the OS to use while you troubleshoot.

SQL's min memory setting I leave alone. I personally have never had a reason to change it.

As Mark said, if this is a dedicated server SQL box then that's good. If you run additional app level services you'll want to lower that max memory so that they'll play nicely together.