Parcel Builder is in preview. Feedback during this period is a valuable driver for its development.
In its current state, Parcel Builder expects from the user to follow some guidelines.
The most important is that for the connector-name you can use only letters and digits.
For the connector version you may use dashes, underscores and dots as well.
Depending on size, parcel creation can take a few minutes. Stay patient and don't refresh your browser.