O365 not working

Community Novice

I have a teacher who has Cloud Books. When he tries to have his students go into the Canvas folder in O365, they can see the file and Attach File. But when they get back into the Submit Assignment area and click Submit Assignment, it just hangs (that aggravating rotating wheel). Any suggestions on how to help the teacher? I have already heard change browsers and delete cache, but does anyone else have another idea. I have had several teachers send me this same problem so I would love to know how to fix it. Any help would be appreciated. Thanks.