Hi @Wojciech,
Thank you for posting in this community.
This can happen due to several reasons, such as browser compatibility issues, web part configuration problems, or even recent updates to SharePoint.
Here are a few steps you can try to troubleshoot and resolve the issue:
- Update Embed Web Part Settings: Edit the web part settings to ensure everything is configured correctly. Sometimes, reapplying the settings can fix display issues.
- Try removing the Embed web part from the page and adding it again.
- You may need to check the permissions of the shared calendar in Outlook and ensure that it is set to allow access to the necessary users.
- Are other users facing the same problem? View through another computer or account.
- Whether all SharePoint pages have the same problem? You could create a new SharePoint page to check.
- Check if the same issue occurs with other SharePoint sites.
- You could try to clear browser cache then restart it.
- Try to use a different browser or your browser's InPrivate mode to see if the same error occurs.
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