PC to MAC over Ethernet Connection - Cant save any project - why?

“The project could not be saved, because: There is not enough space on the disk. No new project could be created.”

This information is displayed to me when I try to save the project. The project files are on the second computer with OSX system (serves as additional disk space). Nuendo works on first PC (Windows 10). Both computers are connected through a router, drives are mapped, and file transfer is hassle-free.
What should be changed to be able to save the project on a second computer. The function does not work on an exFAT formatted drive or Mac OS Extemded.
There is a lot of free space on each disk.
Please help.
Thanks in advance:)

Maybe there are access restriction from OSX?