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Currently in Microsoft Q&A we only support English, could you please edit your question into English?Then we can help to solve your issues, thanks for your understanding.
According to the machine translation, it seems like you're asking about how to set up a fixed time zone when opening a mailbox for the first time and whether there are related commands.
If that's the case, you could let your users set their own time zone in their Outlook Web App (OWA). When the user logs in OWA for the first time, the system will notify them to set their language and time zone. If they made a mistake in the configuration of the time zone, as Wilkin Sanchez suggested, we recommend using PowerShell to set the time zone for all user mailboxes in the Exchange environment. To do this, simply run the following command:
Get-Mailbox -RecipientTypeDetails UserMailbox -ResultSize Unlimited | Set-MailboxRegionalConfiguration -TimeZone "<Your Desired Time Zone>"
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