Conversion from type 'DBNull' to type 'String' is not valid


Description of Error:

The following error appears after logging into the mobile client and attempting to do anything:

MobileDispatchListRequest: Conversion from type 'DBNull' to type 'String' is not valid.

This error generally occurs when you are trying mobile for the first time.

Cause of Error:

There is an invalid dispatch in the system. This is generally caused by missing data, such as a customer that was associated with a dispatch has been deleted. While this is not possible in current versions of ESC, it may have occurred in previous versions.


This issue can be difficult to find as the dispatch will most likely not show on the dispatch board or dispatch lists due to the missing information.

1. On the ESC Connections Server you need to go to Settings → Advanced and check-off Enable Detailed Logging and hit Apply.
2. Try to access the dispatch on your mobile device, again. Once you get the error message, find a workstation/server that has ESC on it, and log in.
3. In ESC, go to Help → About → View Integration Log, in this log you need to look for a number related to a Dispatch.
4. Once you see a dispatch number listed in the integration log, close the log and then go to Dispatch → Enter Dispatches.
5. In the Dispatch field, where you can type in a specific dispatch number, type in the number and hit Tab on your keyboard.
6. This dispatch is problematic. Delete the dispatch. If you don't want to delete the dispatch, you'll need to further investigate. Check the Schedule tab to see if something is missing. The information - or lack of information - should be evident, locate it and fix it.

It is possible that this issue could affect more than one dispatch. If you continue to receive the error, repeat the process until all dispatches are corrected or deleted.

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