Invalid Credentials in BlinkUp SDK in IOS

we have use the BlinkUp IOS sdk demo application…and set out build api key.but its throws me server error

Error Domain=com.electricimp.blinkupSDK Code=80 "Server Responded with Error" UserInfo={serverCode=Problem parsing server code
 data={"error":"Invalid Credentials"}, mimeType=application/json, method=POST, statusCode=400, NSLocalizedDescription=Server Responded with Error} BUConfigId.m:144

we have some research on google for this error…and i found something related to this error.
The Android and iOS BlinkUp SDKs may only be incorporated into mobile apps developed by or for Electric Imp customers. You will require a BlinkUp API Key to authorize every access your app makes to the Electric Imp Cloud via the SDK. Please contact to discuss the advantages of becoming an Electric Imp customer.

but we have use only developer purpose …why we need commercial key for developer key???
please guide me how to tackle this scenario…


The BlinkUp SDK is limited to folks who have a commercial relationship with Electric Imp, ie. customers who pay for our service. This is because customers need the SDK to create the apps that they will supply to the folks who buy their products.

Simply, the SDK is not needed for development, so it’s not made available to folks with free developer accounts. Developers use the Electric Imp app to get their development devices linked to their accounts.

If you need to use the SDK in order to build an app that you can distribute to end-users, then you’ve reached the limit of what your developer account can bring you and you need to enter into a commercial agreement with us.

ok thanks @smittytone.