Your quote was not updated. Enter an Attribute Picklist Value that’s in an active or draft state.

@Abdul Salam Chaudhary

Thanks Abdul,  I really appreciate your response. 

In my case, for one Display Attribute I selected Attribute Values that was in Active status, but for the Screen Size Attribute I had selected a value that was in Draft

status. 

After changing the Screen Size Attribute Value from Draft to Active

, the issue was resolved.