I'd say it's possible there's a typo or some other error in the GATT declaration, like perhaps a handle number out of order. It might be a good idea to create an app from scratch using the WICED Bluetooth Designer / Smart Designer wizard that comes built into the SDK. This will create your GATT database automatically and prevent anything like this from happening, especially since you've got such a large number of attributes. It'll also create the framework for a new application for you to start from.
ankr_1205151 is correct as there is most likely a typo somewhere in your GATT DB declaration.
Since GATT DB creation is heavy on syntax, SmartDesigner is a good tool to use as it will help you avoid alot of the common mistakes.
thanks, this really solved the problem, how embarassing...
Still haven't found the error in the original GATT database, but won't search for it anymore.
Excellent news. Thanks for updating the thread.