Failed to save document (collabora)

#1

Hi,
I have Ubuntu 16.04, Php 7.0.33, Nextcloud 15.0.14, Collabora Online 3.5.2

When I tried documents I got errors
“failed to save document…”
And I saw errors in web-interface

%D0%B7%D0%B0%D0%B2%D0%B0%D0%BD%D1%82%D0%B0%D0%B6%D0%B5%D0%BD%D0%BD%D1%8F%20(1)
%D0%B7%D0%B0%D0%B2%D0%B0%D0%BD%D1%82%D0%B0%D0%B6%D0%B5%D0%BD%D0%BD%D1%8F%20(1)1345×466 64 KB

How I may correct this problem?