Hi @Ihor Polishchuk
We are glad to know that the issue has been resolved. With your permission, we will write a detailed summary report for your reference in case you encounter the same issue in the future, which will also benefit other community members.
In the meantime, are you willing to monitor the issue for another week in case it occurs again? If there is anything else we can do for you, please feel free to contact us.
Symptoms
External users can't see tab content during sharing in meeting
Workaround
To allow external users to view tab contents during a meeting, they should be invited to join a team as guest users.
Expansion
There are two ways to collaborate with people outside your organization: guest access and external access.
- External access - A feature that allows users to find, call, and chat with people who have Microsoft identities, including those from other organizations.
- Guest access - A feature that allows you to invite people from outside your organization to join a team. Guests can also call, chat, and meet with people in your organization and you can share files and folders with them.
Set up external access if you need to find, call, chat, and set up meetings with people outside your organization who use Teams, Skype for Business Server, or Skype. By default, external access is enabled.
Use guest access to add a person from outside your organization to a team, where they can chat, call, meet, and collaborate on files. A guest can be given nearly all the same Teams capabilities as a native team member.
For more information, see Use guest access and external access to collaborate with people outside your organization.
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