Hi @IBN ,
Some of our students are unable to chat 1:1 to teachers personally.
Here is the error "Administrator has disabled chat for this user"
From the second screenshot, seems like the user had been able to chat 1:1 with the teacher previously, right? So is this a suddenly occurred issue after any recent changes in your environment?
For the affected students, please check in Teams web client and see if the error persists there.
Besides, it's suggested to go to Teams admin center, check if these affected users have been assigned a Messaging policy with "Chat" disabled. If yes, please turn on "Chat" and you may need to wait for a few hours(up to 24 hours) for the change to come into effect.
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