Windows Server 2019

I have a Nextcloud Install on Linux, and have managed to sync all the files I have on it with all my computers, except one.

I have a Windows Server 2019 install, that was initially rejecting the host’s certificate and now that I changed the certificate, started working, but, I am having problems syncing certain kinds of files, for example .pdf, .dll, .jpg, etc. files, as apparently Windows Server will not let the Nextcloud client write them in the drive, or folder.
It is writing some of them but not all of the files and the sync stops.
Are ther any settings that need to be changed in Windows Server so the nextcloud client works ?
Thanks

Manolo