error while testing API

GrabzIt Error: Your current package does not support encrypting captures. Upgrade for free to encrypt captures: https://grabz.it/upgrade/?FreeTrial=true

before upgrade my account, i'm testing the api.

but error has been occurred.

i didn't set any parameters 

GrabzIt("key").ConvertURL("my domain address").Create();

how can i fix this problem?

I am unable to repeat your problem. Using the call you referenced above:

GrabzIt("key").ConvertURL("my domain address").Create();

Generates a capture. The only way I can recreate your problem is by using:

GrabzIt("key").Encrypt().ConvertURL("my domain address").Create();

Which is the correct behaviour as capture encryption is a premium feature. To use premium features free for seven days you can try our বিনামূল্যে ট্রায়াল.