frequently the server is going down.while going through the log we find out this error!!!

i have 22 active users and i assigned 3 workers in odoo config file

Traceback (most recent call last):
File "/odoo/odoo-server/odoo/http.py", line 654, in _handle_exception
return super(JsonRequest, self)._handle_exception(exception)
File "/odoo/odoo-server/odoo/http.py", line 312, in _handle_exception
raise pycompat.reraise(type(exception), exception, sys.exc_info()[2])
File "/odoo/odoo-server/odoo/tools/pycompat.py", line 87, in reraise
raise value
File "/odoo/odoo-server/odoo/http.py", line 696, in dispatch
result = self._call_function(**self.params)
File "/odoo/odoo-server/odoo/http.py", line 344, in _call_function
return checked_call(self.db, *args, **kwargs)
File "/odoo/odoo-server/odoo/service/model.py", line 97, in wrapper
return f(dbname, *args, **kwargs)
File "/odoo/odoo-server/odoo/http.py", line 337, in checked_call
result = self.endpoint(*a, **kw)
File "/odoo/odoo-server/odoo/http.py", line 939, in __call__
return self.method(*args, **kw)
File "/odoo/odoo-server/odoo/http.py", line 517, in response_wrap
response = f(*args, **kw)
File "/odoo/odoo-server/addons/bus/controllers/main.py", line 37, in poll
raise Exception("bus.Bus unavailable")
Exception: bus.Bus unavailable