Your scenario is somewhat vague so it's difficult to guess. You might be talking about MAPI connecting to an Exchange server. The Exchange server you might be talking about might be throttling your connection if you're hammering the server. You can turn on throttling logging here:
http://howexchangeworks.com/2012/07/enable-logging-for-rpc-client-access-throttling.html
And if you are being throttled, you can look at these throttling policies:
http://technet.microsoft.com/en-us/library/bb232205(v=exchg.150).aspx#Policies
You can also look at building your client so as not to hammer the server so hard, such as ensuring you close items after you open them, or using the contents table to get information about items instead of opening the item to get it - stuff like that.
Next time, you might want to be more specific about your scenario. Also, if you're getting errors, say what they are.
http://howexchangeworks.com/2012/07/enable-logging-for-rpc-client-access-throttling.html
And if you are being throttled, you can look at these throttling policies:
http://technet.microsoft.com/en-us/library/bb232205(v=exchg.150).aspx#Policies
You can also look at building your client so as not to hammer the server so hard, such as ensuring you close items after you open them, or using the contents table to get information about items instead of opening the item to get it - stuff like that.
Next time, you might want to be more specific about your scenario. Also, if you're getting errors, say what they are.