When trying to activate a blackberry and getting a error “The Server is not responding, please contact your system administrator”.  The Activating… status stops responding for 10 minutes, retrying every 10 minutes with a Retrying… status. After 40 minutes, the process times out with this message:
The server is not responding. Please contact your System Administrator.

Causes for this behavior include the following:

An incorrect password was entered on the device multiple times.
The user account mailbox is full, or the messaging server is unable to send or receive messages.

SMS Service Centre number: +447785016005.
This number is used to configure your phone for sending text messages.

Handset’s serial number:Enter ‘*#06#’ as a phone number, to get your handset’s serial number (known as the IMEI)

Other useful codes You can also try the following network commands:

*#100# = Your own mobile phone number
*#103# = The current time from the network

While traveling sometime users are not able to receive emails on the blackberry but still able to send. To fix this try the follwoing
Open emails
Options
Email settings – click on bb symbol
Folder redirection
Expand and change inbox

For some reason box not ticked if you select this.

If you do need additional ring time before voicemail:

A) The simplest method is to call your carrier and request a longer ring time, up to 30 seconds.

B) If you have a GSM based phone, some have had success by dialing this number from your phone: **61*XXXXXXXXXXX**30#

Replace XXXXXXXXXXX with the number of your carrier voice mail center (find it by looking at your Phone Dialer > Options > VoiceMail > Access Number. Put your access number in place of the Xs above.
For example, the Vodafone uk voice mail access number is 121, and thus the string to dial would be **61*18056377243**30#

Replace the 30 at the end of the string with your desired seconds. For most carriers, 30 seconds is the longest allowed.

There is a number of ways to trouble shoots this common issue on the blackberry and can sometimes be an easy fix and other times it can take a few troubleshooting steps.
When the BlackBerry user attempts to send a Messageing message it fails immediately. A red X appears and the following error is received. Some times it can be that you are not able to send or receive emails and no error shows.
The error could be caused by one of the following:
The BlackBerry user is attempting to send a message without having a data plan.
The service book is currupt.

Resolution
To correct this issue follow the steps below:
Some times perfoming a hard rest of the device can solve this issue.
Verify that the BlackBerry has a Data Plan.
Delete and resend the Desktop CMIME service books in Options > Advanced Options > Service Book.
Perform a hard reset on the BlackBerry.