Hello, I'm running odoo V8, and after checkout process, I'm redirected to '/shop' instead to '/shop/checkout'.

I took a look to the odoo server log, and it seems to be a problem with the confirmation process:

2018-07-03 16:07:40,484 31815 INFO dgm openerp.addons.payment_transfer.controllers.main: Beginning form_feedback with post data {'amount': u'337.53',
 'currency': u'EUR',
 'reference': u'PV/2018/0382',
 'return_url': u'/shop/payment/validate'}
2018-07-03 16:07:40,488 31815 INFO dgm openerp.addons.payment_transfer.models.payment_acquirer: Validated transfer payment for tx PV/2018/0382: set as pending
2018-07-03 16:07:40,521 31815 INFO dgm openerp.addons.website_sale.models.payment: <transfer> transaction processed: tx ref:PV/2018/0382, tx amount: 337.53
2018-07-03 16:07:40,523 31815 INFO dgm openerp.addons.website_sale.models.payment: <transfer> transaction pending, sending quote email for order PV/2018/0382 (ID 2675)
2018-07-03 16:07:40,546 31815 ERROR dgm openerp.sql_db: Programming error: EXCEPT types record and integer cannot be matched
LINE 2: ...t(ARRAY[(6, 0, '{}')])) EXCEPT (SELECT wizard_id, partner_id...
                                                             ^
, in query  INSERT INTO mail_compose_message_res_partner_rel (wizard_id, partner_id)
                        (SELECT %s, unnest(%s)) EXCEPT (SELECT wizard_id, partner_id FROM mail_compose_message_res_partner_rel WHERE wizard_id=%s)

2018-07-03 16:07:40,546 31815 ERROR dgm openerp.addons.website_sale.models.payment: Fail to confirm the order or send the confirmation email for the transaction PV/2018/0382
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/openerp/addons/website_sale/models/payment.py", line 41, in form_feedback
    self.pool['sale.order'].force_quotation_send(cr, SUPERUSER_ID, [tx.sale_order_id.id], context=context)
  File "/usr/lib/python2.7/dist-packages/openerp/api.py", line 268, in wrapper
    return old_api(self, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/openerp/addons/sale/sale.py", line 684, in force_quotation_send
    composer_id = composer_obj.create(cr, uid, composer_values, context=email_ctx)
  File "/usr/lib/python2.7/dist-packages/openerp/api.py", line 268, in wrapper
    return old_api(self, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/openerp/addons/mail/mail_message.py", line 814, in create
    newid = super(mail_message, self).create(cr, uid, values, context)
  File "/usr/lib/python2.7/dist-packages/openerp/api.py", line 268, in wrapper
    return old_api(self, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/openerp/api.py", line 372, in old_api
    result = method(recs, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/openerp/models.py", line 4101, in create
    record = self.browse(self._create(old_vals))
  File "/usr/lib/python2.7/dist-packages/openerp/api.py", line 266, in wrapper
    return new_api(self, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/openerp/api.py", line 508, in new_api
    result = method(self._model, cr, uid, *args, **old_kwargs)
  File "/usr/lib/python2.7/dist-packages/openerp/models.py", line 4292, in _create
    result += self._columns[field].set(cr, self, id_new, field, vals[field], user, rel_context) or []
  File "/usr/lib/python2.7/dist-packages/openerp/osv/fields.py", line 1046, in set
    link(act[2])
  File "/usr/lib/python2.7/dist-packages/openerp/osv/fields.py", line 1016, in link
    cr.execute(query, (id, list(sub_ids), id))
  File "/usr/lib/python2.7/dist-packages/openerp/sql_db.py", line 171, in wrapper
    return f(self, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/openerp/sql_db.py", line 247, in execute
    res = self._obj.execute(query, params)
ProgrammingError: EXCEPT types record and integer cannot be matched
LINE 2: ...t(ARRAY[(6, 0, '{}')])) EXCEPT (SELECT wizard_id, partner_id...