Some Blackberrys slow to receive e-mails (using BES)

Posted on 2009-07-03
Last Modified: 2012-05-07
We have over 200 Blackberry's, and recently a few have started receiving e-mails very slowly.  It can take several hours for an e-mail to arrive on their Blackberry (arrives in Outlook immediately).  Usually the user will receive a bunch of messages at once, then will go another extended period without receiving e-mails.  Most of our Blackberry's, however, are working fine.

There does not seem to be anything in common with these users -- they are on different Exchange servers, in different parts of the company, and are running different models and software on their Blackberry's.

With one user I wiped her handheld, deleted and recreated her account on the BES, then reactivated her Blackberry.  This has seemed to resolve her problem, but I'd like to find an actual solution rather than a "workaround."

I also found a couple articles saying to remove the CDO entries from the registry on the BES, then restart the BES server.  I did this (we probably had over 1000 entries), but the same users are still having delays.  If I look in the BES Administrator, it will show pending messages, and no contact with the Blackberry for an hour or several hours.

Anyone experienced a similar problem, or have any suggestions?

Question by:Enterprise_IT
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Expert Comment

ID: 24773805
I heard that cache mode on outlook is known to cause this issue, i have no idea why this would cause it on a BE server but i heard this from a BES engineer with the company.
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Assisted Solution

-jonny- earned 150 total points
ID: 24774254
Often message delays are due to MAPI errors, which can be down to latency between BES and exchange mail stores.

Firstly, how many exchange servers do you have? The BES will create messaging agents dynamically, which are responsible for maintaining the MAPI connections to each mail store for your users. However, the preset max limit is 4, which may be too few for the number of users spread over the number of mail servers.

When messaging agents get overloaded all the email processing gets backed up (as well as every other process/task running on the BES), resulting in delays in message delivery.

You can increase the default number of messaging agents by modifying the following registry key:
HKLM\SOFTWARE\Research In Motion\BlackBerry Enterprise Server\Dispatcher\MaxUsersPerAgent

HOWEVER, be careful. Increasing the number of messaging agents significantly increases the load on your server. If you have a highly-spec'd BES (processor, memory etc) then try increasing it a few at a time. You will need to restart the BES in order for the changes to take place.

If that doesn't work, you can try assigning trouble users to the same messaging agent. I would assign users on the same mailstore to the same messaging agent as that will isolate the problem users without affecting other users.

Author Comment

ID: 24774790
I don't think it's latency, since it is affecting a small number of users (5 - 10) on a regular basis, but all other users (200+) are working fine.

We have 3 Exchange servers, but most of the users are split between 2 Exchange servers.  The problem users are on both of these servers, and different Information Stores, so I don't think the Exchange servers are the issue.

The registry key was not there by default so I had to create it.  However I wasn't sure what type of key to make it so I made it a REG_DWORD key since that is what most of the other keys appear to be.  Should it be a Binary key instead?  I tried increasing this value to 600 (from the default 500), but don't know yet if this resolved the problem.

To check and assign a messaging agent, do I go to Properties -> Advanced -> Mailbox Agent ID?  Or do I need to look somewhere else.

Thank you.
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Expert Comment

ID: 24775891
Do the problem Blackberries have the delay consistently or intermittently. I suspect the latter and it may be related to network coverage. If these folks are roaming around a lot or entering low reception areas, it can shutdown data services (undersirable "feature"). Does rebooting the handheld device do anything helpful?

Do these users have general internet access (i.e. can they reach sites like on their browser) during periods of email delay?

What's the carrier or carriers that are having problems? Is there a common factor?

If reception is an issue, you may benefit from updating the PRL on some networks (i.e. *228 on Verizon).


Author Comment

ID: 24777035
We cannot find any common factors -- some are on Verizon, some on TMobile (and others on these providers are not having problems); they are on different Exchange servers; and in different areas of the country.  The delays are consistent, even when they are in areas that we know have excellent coverage.  There are no Internet or other data slowness issues when they are having e-mail delay issues.

Rebooting does not help.  The only thing that seems to resolve the problem is to wipe the handheld, remove the user from BES and re-add them, then reactivate the handheld.  However this is a lot of trouble to go through for the users, plus I want to figure out why they are having these issues and fix it permanently, rather than use this "workaround."


Expert Comment

ID: 24777330
I'm like that to, opting to figure out the problem over workarounds. Ahh, consistent problem. Not good, but sometimes easier to track down than intermittent ones. As I understand the problem, messages are delayed for hours (is this time period variable; what's the longest delay and the quickest delivery?) but not lost. It's still not clear to me if the problem is on the server or client. Your workaround requires fixes on both ends. Have you isolated the issue to the server side? What have you done along the lines of keeping the account of the server untouched, but wiping out a handset and resyncing or going further to transfering the account to a new device (again, keeping hands off server side)? I assume you've already tried these, but may be worth mentioning again: restore service books, taking out battery as part of reboot, and updating host routing tables

Is email/attachment size an issue?

BTW, you said, "If I look in the BES Administrator, it will show pending messages, and no contact with the Blackberry for an hour or several hours." No contact with blackberry means I'm still concerened with connection issues. Appears client has access to internet, server is also connected, but they're not connecting to each other (partial or completely). Food for thought.

It's an odd corruption that breaks at one time, but works later. The fact that it works later means something broken is automatically repaired, or a timed process is providing backup delivery.  Are restoration of service (delivery of delayed email) related to any events or time of day?  Or are delays consistent in a any way (time of day) or totally random?

Anything else running on the BES or is this a dedicated server? It probably doesn't matter, since only impacts small fraction of users, but just to be thorough. On the same note, is there any additional or 3rd party software on the clients?

How is the performance on outgoing mail on these problematic accounts/units? I assume that they're delayed as well, no?

Have you looked to see if anything unusual is present on the error logs that might give a clue or do you have BlackBerry Enterprise Server Resource Kit running? Do any error indicate anything more than simply loss of connection to the client?

From the sound of it, my gut is pointing to a loss of connection that gets restored automatically.

Accepted Solution

Enterprise_IT earned 0 total points
ID: 24787097
The problem appears to be fixed.  It looks like a combination of installing BB SP6, then adding the MaxUsersPerAgent registry key, then stopping all Blackberry services and clearing the CDO entries from the registry, then rebooting the Blackberry server, fixed the problem.

Thanks for the help, everyone.

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