Hi @Victoria ,
Currently in Microsoft Q&A we only support English, could you please use English in the following description? Then we can help to solve your issues. And we are researching based on machine translation, I understand that your Outlook automatically changes back to the time your previous region.
Did you change it on the client or on OWA?
If you want to change the time zone for your Office 365 account, you can refer to this article.
After changing time zone, you also need to change the configuration to apply this one to your calendar on OWA:
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