Are you using the legacy version of Microsoft edge and have not updated to the new Microsoft Edge we have some bad news. Whatsapp-web dropped support for legacy Microsoft web browser.
WhatsApp web on the legacy edge will give an error message that WhatsApp works with Microsoft edge 80+. This message notifies to update Windows 10 to get the latest version of Edge and suggest using Chrome Firefox or Opera.
WhatsApp and other developers have given up the legacy version of edge but Microsoft is holding it. The Xbox series X and Xbox series S uses the old version of Edge. The Windows sandbox in the latest Windows also has the legacy edge pre-installed in the sandboxed Windows 10.
The edge browser is part of the Xbox operating system. It will be interesting if Microsoft ports the new browser to Xbox OS. Microsoft has done this with HoloLens and Windows 10x.