Hello Cerstin,
What makes it even more confusing is that it works perfectly fine on your mobile, which shows the account itself is okay. This issue is often related to browser conflicts, extensions, or cached data that doesn’t clear properly on Chrome OS. You can try opening Outlook.com in an incognito window, disabling all browser extensions, or resetting site permissions for Outlook.
Flushing the DNS cache via chrome://net-internals/#dns and clicking “Clear host cache” might also help. If none of that works, using another browser like Microsoft Edge (if available on your Chromebook) or resetting Chrome settings to default could be worth trying.
This might help
https://helpdeskgeek.com/how-to-fix-something-went-wrong-error-in-microsoft-outlook/
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