I have surveys that all users can complete in the Survey123 mobile app. However, they cannot open the survey to complete in survey123 online. Note in the picture below I have a "open survey" link, other users do not have this option.
How do you share the survey? When you say "All users" do you mean in your org?
make sure that you shared it for probably or it will just be a View HFL where they can't edit.
Also, check their levels and their roles
It is shared to an organization group, and accessed through a group folder. All of the users are in the organization. They do not have a problem accessing the survey from the mobile app. It is just from the Online Platform. They can all review and analyze data, just cannot open the survey link from the online portal.