Collabora Online gray screen when open file from external storage


My Nextcloud is installed as app in UCS VM. (which mean Nextcloud is docker container)
Nextcloud is attached to external storage SMB with windows shared folders.
when i open file from Document local folder files is opened as expected:

but when i try to open file from the shared folder (external storage) i get a gray screen:

I googled a lot and noting of it is the solution.

can anyone help me to solved it?

Thanks a lot

I just find the solution by disabling the watermarking in Collaborate Online configuration: