Example with console log https://prnt.sc/GfsgOqfapypn

Also I think this is because of this error:

Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/odoo/addons/base/models/ir_http.py", line 237, in _dispatch
result = request.dispatch()
File "/usr/lib/python3/dist-packages/odoo/http.py", line 687, in dispatch
result = self._call_function(**self.params)
File "/usr/lib/python3/dist-packages/odoo/http.py", line 359, in _call_function
return checked_call(self.db, *args, **kwargs)
File "/usr/lib/python3/dist-packages/odoo/service/model.py", line 94, in wrapper
return f(dbname, *args, **kwargs)
File "/usr/lib/python3/dist-packages/odoo/http.py", line 348, in checked_call
result = self.endpoint(*a, **kw)
File "/usr/lib/python3/dist-packages/odoo/http.py", line 916, in __call__
return self.method(*args, **kw)
File "/usr/lib/python3/dist-packages/odoo/http.py", line 535, in response_wrap
response = f(*args, **kw)
File "/usr/lib/python3/dist-packages/odoo/addons/bus/controllers/main.py", line 28, in poll
raise Exception("bus.Bus unavailable")
Exception

Check the browser console and see whether you get some hints over there. It may be caused by JS changes.

Had the same issue. Safari and Chrome app. Fixed itself by updating to last ios version.