According to your description, are you using Microsoft 365 apps instead of Office 2016?
If yes, please refer to this article first. “"Sorry, we can't connect to your account. Please try again later" error when you activate Office from Office 365”.
There are some troubleshoot steps, you may have a look.
In addition, please note, TLS 1.0 and 1.1 support is being deprecated by Microsoft. If your connections for Office services rely on these TLS protocols, it's best to remove the dependencies on TLS 1.0 and 1.1 and upgrade to TLS 1.2 as soon as possible.
For more information, please refer to "Update to enable TLS 1.1 and TLS 1.2 as default secure protocols in WinHTTP in Windows".
Any updates, please let me know.
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