Link to a cell in a table in another Collabora table

We are using Nextcloud on the server and have installed the Collabora extension. We need to be able to link spreadsheets cells to other spreadsheets cells. How can we do this? We tried the formula:


but it didn’t work. Status bar says “External content disabled: undefined”. Perhaps we specified the file name incorrectly and we need to specify the full path there, but then it is not clear what format it should have