I am trying to create a hosted page to create a new subscription with a plan and an associated addon. The hosted page is created only with the plan and not with addon.
{'additional_param': 'New Subscription',
'addons': [{'addon_code': 'silver_addon', 'quantity': 1}],
'customer': {'billing_address': {'city': ' Ashton Road',
'country': 'United Kingdom',
'state': '',
'street': '150 B,',
'zip': 'OL8 1QT'},
'currency_code': 'GBP',
'custom_fields': [{'label': 'UNIQ', 'value': '1111111111'},
{'label': 'year', 'value': '2015'}],
'display_name': 'zoho Subscription',
'first_name': 'zohoprevious',
'last_name':'Previous',
'payment_terms': 1,
'payment_terms_label': 'Due On Receipt',
'shipping_address': {'city': 'Ashton road',
'country': 'United Kingdom',
'state': '',
'street': '150 B',
'zip': 'OL8 1QT'},
'vat_treatment': 'uk'},
'plan': {'exclude_setup_fee': true,
'exclude_trial': true,
'plan_code': 'previous_year_plan',
'quantity': 1},
'starts_at': '2017-04-06'}