Which Windows System does this user use?
Do other users in organization encounter the same problem?
I would suggest this user check TLS protocols, please note TLS 1.0 and 1.1 support is being deprecated by Microsoft.
For more please refer to "Update to enable TLS 1.1 and TLS 1.2 as default secure protocols in WinHTTP in Windows".
It's recommended to disable the Proxy Settings if this user uses a proxy server for LAN.
If nothing helps, please reset OneDrive client to have a look.
Besides, here is an artcile "Error Code 0x8004de40 when signing in to OneDrive", you may have a look.
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