could be not enough ram, too low page file settings, you should run a performance base line on the server. and maybe start a counter log to see what takes a nose dive when you try to access the database.
There are so many reason why happend Insufficiant system error message in domino.
So if you solve the problem, first give us more detail server log.
In my case, a couple of days ago our mail server also happend insufficient memory like you said.
I looked at server console log more detail. and finally i found the exactly reason in notes.net.
below document was our server’s problem.
Mass mailing causes Router to run out of memory and enter a hang state
When a mass mailing containing an in-line attachment is sent, Router stops routing mail and enters a hang state. One or more of the following errors appear in the server’s log.
“Router: Error transferring message X via Notes to serverX mail.box Insufficient memory”
“Unable to add note X to folder in Database X.nsf: Insufficient memory – NSF folder pool is full”
“Unable to add note X to folder in Database X.nsf: Insufficient memory”
“CD to MIME error (Process: Router (X), Database: /serverX/mailX.
box, Note: X): Insufficient memory”
Router runs out of private memory when attempting to deliver a message that is large in size to a large number of recipients. A message with an in-line attachment can easily fit this description. The private memory block affected in this case is shown below:
+75 xxx xxxxxxx PRCHDL BLK_OPENED_NOTE – NOTE pool for existing note
A workaround to prevent a mail message such as the one described above from being sent and stopping the flow of mail is to add the following INI parameters. These parameters are available beginning in the Domino version 7.0.1 code stream:
When enabled, this restriction will cause the Router to NDF (Non-Delivery Failure) a message when the number of recipients * multiplied by the message size (in k bytes) is greater than the value specified by the ini setting. Attachments are excluded. The value of the INI setting is set in KB.
With this enabled, it includes the attachment in the equation on the size of the message
Note: The above INI parameters are valid for the specific server. If the users are on multiple servers and the limit is not set on any of them, the mailing will still happen.
Another possible workaround is to limit the number of threads that are used for sending large messages. Refer to the following technote for details: How to limit the number of threads used for sending large messages (#1108351)
So you also have to look at server’s log more detail.