I can not reload Rainloop with browser reload button

[Bables55]

RainLoop version, browser, OS:
Rainloop: 1.12.1
Firefox: 63.0.3, Vivaldi: 2.1.1337.51 iOS Safari

Expected behavior and actual behavior:
When I press the update button of the browser in any process, it becomes display of only the background picture of Rainloop and I can not operate anything.
The problem does not occur only when accessing "https://MYDOMAIN/dir/rainloop/?admin".
This problem does not occur unless I log in.

Steps to reproduce the problem:
Access the Rainloop with the PC or smartphone, and I will login.
Next I make the reload of the Web browser itself function.

To use Rainloop again, clear the cache or reopen the browser.

I am trying Rainloop with Gmail and a general email account. Both and only one.
In either method, when I press the reload button, it becomes inaccessible.

Logs or screenshots:
Develop tool:
GET https://MYDOMAIN/dir/rainloop/?/AppData@no-mobile-0/_9YnIsSJef0KUF4NXRIfu2UdEN04sBx9gMuDDo-jD4qCHNOBfMMVKNjgNtOAS2ekj4nAWtrBDFe-KNtQU5sfM0sJrMJGFbzfS7VYiMXtLHCxgOWgXqpck4OYZrJYz88TszKmEuBvn1Xtns5TiFyhCOEZlPSUwVHdaeyrvcpiaJ8xcC7PBH-5JvaftGj8Hb5baBMjWgFqcoDg0KAV-ebKSfHn4D4heirtQj_vP_CuJYalg4zfKiUs3UOkPJMm1vco5o_CAZUGubpCnhVAm7zfw0DbRXEHRXXSxW4slHAhBCD-lzx1Ffum-HcALtpfKipVHYTtUurw18dNhWQZk9W80tJv0UBJ868yTIzGoL3TfOGlFDPio/16345972199007708/[HTTP/2.0 403 Forbidden 24ms]

boot.min.js?

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