Explanation
1. User is able to login but can't see Case Records --> "Configure Mobile Settings on Case Entity Level"
2. Users can open cases but cannot see the subject of the case - "configure mobile settings at the field level within the case form
3. User reports that they cannot access the system from Dynamics 365 mobile app --> Configure a security role in the mobile permission set of the appropriate user
https://docs.microsoft.com/en-us/dynamics365/customer-engagement/mobile-app/set-up-dynamics-365-for-phon

Explanation
Box 1: Language packs
Before users can start using a Language Pack to display a language, the Language Pack must be enabled in your organization.
Box 2: Environment
Enable the language
These settings can be found in the Microsoft Power Platform admin center by going to Environments > [select an environment] > Settings > Product > Languages.
Reference: https://docs.microsoft.com/en-us/power-platform/admin/enable-languages

Reference:
https://docs.microsoft.com/en-us/power-platform/admin/use-service-admin-role-manage-tenant
https://community.dynamics.com/crm/b/govandthecity/posts/understanding-dynamics-365-and-office-365-admin-roles

When embedding a Power BI tile in a Canvas app, there are several factors that must be considered in order to ensure that users have access to the content. One of the most important is sharing the Power BI dashboard that the tile is embedded in. If the dashboard is not shared with the users, they will not be able to view the content in the tile.
To share a Power BI dashboard, you must have the "Edit" permission for the dashboard. Once you have this permission, you can share the dashboard with other users by following these steps:
Open the Power BI service and navigate to the dashboard that you want to share.
Click the "Share" button in the top-right corner of the dashboard.
In the "Share" pane that appears, enter the email addresses of the users that you want to share the dashboard with.
Select the level of access that you want to grant to the users. You can choose to give them "View" access, which allows them to view the dashboard but not make changes, or "Edit" access, which allows them to view and make changes to the dashboard.
Click the "Share" button to share the dashboard with the users.
Additionally, there are other factors that could cause user's problems:
B) The Power Bl interactions property on the Power Bl tiles is set to Off. In that case, the user's won't be able to interact with the visuals.
C) The Power Bl connection is not shared. In that case, the user's won't have the access to the data source D) The Power Bl Display mode property on the Power Bl tiles is set to Disabled, in that case the user's won't see the tile It is important to check all of these factors and ensure that they are properly configured in order to ensure that users have access to the content.
Reference:
https://docs.microsoft.com/en-us/power-bi/service-admin-share-dashboard
https://docs.microsoft.com/en-us/powerapps/maker/canvas-apps/embed-power-bi
https://docs.microsoft.com/en-us/power-bi/service-embed-content/embed-in-powerapps