What account do you use? Outlook.com or Exchange account?
Do you log on mailbox via browser?
Please first clear browser's cache and temporary internet files to make sure that this is not a browser issue. You may also try to access your email using a different web browser.
- Click the Menu icon in the top right corner and choose Settings.
- Scroll all the way down and click on Advanced
- Now locate Clear browsing data option and click it

To clear the temporary internet files:
- Select Start > Control Panel > Network and Internet > Internet Options.
- Select the General tab, and then select Delete under Browsing history.
- Select Delete all > Yes > OK.
If these steps don’t work, please paste the whole error message here for further research.
Regards,
Perry
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