folder/file permission on standard channel for team members

[Ana-S]

I have a standard channel with folder/files, and team members have  default edit access permission. I would like to set the team member permission to read only or restricted view, so they can view but not edit or download the files. 

When I open the channel in SharePoint, change the team member permission through Manage access from Edit to Read/Restricted view, members no longer see the files. 
Why are files not visible for team members when the member permission is changed from Edit to Read/Restricted View?

[#2]

@Ana-S 

Since the community has not yet responded to your post, you might want to seek assistance with other resources that are focused on tech support:

• Ask your IT manager to open a support case or call Microsoft using the support line you were given.  Other options for business subscription admins are listed here:

Get support | Microsoft Docs

https://support.serviceshub.microsoft.com/supportforbusiness/create

Additional tech support is available at support.microsoft.com or Answers.microsoft.com, where authorized Microsoft agents are available to trouble an issue until it’s resolved.

[#3]

Thank you Therese. I appreciate your help.