Problems collaborating on iCloud

I have an Apple Mac running macOS High Sierrra V10.13.2. I have produced a spreadsheet in Numbers and wish to share this with others at my Golf Club. In the past this has worked, even with those who have a PC running MS Windows. Sharing my latest spreadsheet this year has proved to be very difficult. Some of those I am collaborating with have no problem going access, including those using an Apple Mac and one member using a very old PC running Widows XP. However most of those I wish to collaborate with have been unable to gain access, this includes those with PCs running MS Windows and those using Apple products such as iPads. All have an iCloud account but still cannot gain access. Does anybody have any idea who I am having this problem? Any advice is welcome.