>>>The customer sent me an email indicating that the server (hosting SQL Server) has 8 GB. And the value in the Maximum memory is 2147483647 MB. Does it mean they have no limitation? Or, should the Maximum memory number should be changed to?
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>>?2147483647/1024**2
>>gives 2048, so that limitation is set to two terabytes. It's still a limitation, although a bit above the physically possible.
>
>I wonder if this limitation (very high) actually sets Max Limit to No limit (practical) and therefore causes the problem where the SQL Server stops after some time.
>Which brings me to a question (to which I do not know the answer); what would you set the Maximum memory value in order to set a limit and prevent the SQL Server from stopping?

Just shut down the SQL server and check how much available memory the system has then - use task manager to see that. Then set the limit to about two thirds of that. It's quite possible that the SQL engine has all the memory it may need, but the rest of the machine is starved, so the filesystem, networking etc may suffer and thus become the bottleneck. So leave some air for the system.
That would be where I'd start.