Communication List is always empty for users without System Manager role

I gave a user the role Inbox user and he should be able to see all communication entries. The role has permissions to read and select.

Permission Inspector shows:
User has following roles: [‘Sales Manager’, ‘Analytics’, ‘Accounts Manager’, ‘Support Team’, ‘Manufacturing User’, ‘Manufacturing Manager’, ‘Script Manager’, ‘Knowledge Base Editor’, ‘Projects User’, ‘Agriculture User’, ‘Fulfillment User’, ‘Sales Master Manager’, ‘Inbox User’, ‘Stock Manager’, ‘Supplier’, ‘Projects Manager’, ‘Knowledge Base Contributor’, ‘Auditor’, ‘Purchase Master Manager’, ‘Translator’, ‘Quality Manager’, ‘Purchase User’, ‘Dashboard Manager’, ‘Newsletter Manager’, ‘Delivery User’, ‘Website Manager’, ‘Sales User’, ‘Report Manager’, ‘Maintenance User’, ‘Delivery Manager’, ‘Workspace Manager’, ‘Stock User’, ‘Prepared Report User’, ‘Purchase Manager’, ‘Blogger’, ‘Agriculture Manager’, ‘Accounts User’, ‘Maintenance Manager’, ‘Item Manager’, ‘All’, ‘Guest’, ‘Desk User’]

User has following permissions using role permission system: {
“amend”: 1,
“cancel”: 1,
“create”: 1,
“delete”: 1,
“email”: 1,
“export”: 1,
“has_if_owner_enabled”: false,
“if_owner”: {},
“import”: 1,
“print”: 1,
“read”: 1,
“report”: 1,
“select”: 0,
“share”: 1,
“submit”: 1,
“write”: 1
}

User is not affected by any user permissions

Final applicable permissions after evaluating user permissions: {
“amend”: 1,
“cancel”: 1,
“create”: 1,
“delete”: 1,
“email”: 1,
“export”: 1,
“has_if_owner_enabled”: false,
“if_owner”: {},
“import”: 1,
“print”: 1,
“read”: 1,
“report”: 1,
“select”: 0,
“share”: 1,
“submit”: 1,
“write”: 1
}

Controller permission check from frappe.core.doctype.communication.communication.has_permission: True

User has following roles: [‘Sales Manager’, ‘Analytics’, ‘Accounts Manager’, ‘Support Team’, ‘Manufacturing User’, ‘Manufacturing Manager’, ‘Script Manager’, ‘Knowledge Base Editor’, ‘Projects User’, ‘Agriculture User’, ‘Fulfillment User’, ‘Sales Master Manager’, ‘Inbox User’, ‘Stock Manager’, ‘Supplier’, ‘Projects Manager’, ‘Knowledge Base Contributor’, ‘Auditor’, ‘Purchase Master Manager’, ‘Translator’, ‘Quality Manager’, ‘Purchase User’, ‘Dashboard Manager’, ‘Newsletter Manager’, ‘Delivery User’, ‘Website Manager’, ‘Sales User’, ‘Report Manager’, ‘Maintenance User’, ‘Delivery Manager’, ‘Workspace Manager’, ‘Stock User’, ‘Prepared Report User’, ‘Purchase Manager’, ‘Blogger’, ‘Agriculture Manager’, ‘Accounts User’, ‘Maintenance Manager’, ‘Item Manager’, ‘All’, ‘Guest’, ‘Desk User’]

User has following permissions using role permission system: {
“amend”: 0,
“cancel”: 0,
“create”: 1,
“delete”: 1,
“email”: 1,
“export”: 1,
“has_if_owner_enabled”: true,
“if_owner”: {},
“import”: 0,
“print”: 1,
“read”: 1,
“report”: 0,
“select”: 1,
“share”: 0,
“submit”: 0,
“write”: 0
}

User is owner of document, so permissions are updated to: {
“amend”: 0,
“cancel”: 0,
“create”: 1,
“delete”: 1,
“email”: 1,
“export”: 1,
“has_if_owner_enabled”: true,
“if_owner”: {},
“import”: 0,
“print”: 1,
“read”: 1,
“report”: 0,
“select”: 1,
“share”: 0,
“submit”: 0,
“write”: 0
}

User is not affected by any user permissions

Final applicable permissions after evaluating user permissions: {
“amend”: 0,
“cancel”: 0,
“create”: 1,
“delete”: 1,
“email”: 1,
“export”: 1,
“has_if_owner_enabled”: true,
“if_owner”: {},
“import”: 0,
“print”: 1,
“read”: 1,
“report”: 0,
“select”: 1,
“share”: 0,
“submit”: 0,
“write”: 0
}

Output of has_permission: True

But the communication list stays empty and the user is not able to see even his own communications. When I try to open a specific link of an email in the inbox, the user is able to open and see it.

What am I doing wrong here?