I have odoo 11 installed on ubuntu 18.04.  
After having backed up my database, it won't let me in.
Checking the status window I get the following error and I don't know what to do:

 2019-09-01 15:25:47,296 2914 ERROR SQM odoo.addons.base.ir.ir_cron: Call from cron Update SLA Timer for server action #637 failed in Job #11
Traceback (most recent call last):
  File "/home/alfa/Developments/odoo11/odoo/odoo/addons/base/ir/ir_cron.py", line 102, in _callback
    self.env['ir.actions.server'].browse(server_action_id).run()
  File "/home/alfa/Developments/odoo11/odoo/odoo/addons/base/ir/ir_actions.py", line 540, in run
    eval_context = self._get_eval_context(action)
  File "/home/alfa/Developments/odoo11/odoo/addons/mail/models/ir_actions.py", line 61, in _get_eval_context
    eval_context = super(ServerActions, self)._get_eval_context(action=action)
  File "/home/alfa/Developments/odoo11/odoo/odoo/addons/base/ir/ir_actions.py", line 496, in _get_eval_context
    model = self.env[model_name]
  File "/home/alfa/Developments/odoo11/odoo/odoo/api.py", line 760, in __getitem__
    return self.registry[model_name]._browse((), self)
  File "/home/alfa/Developments/odoo11/odoo/odoo/modules/registry.py", line 179, in __getitem__
    return self.models[model_name]
KeyError: 'website.support.ticket'