Before restarting your machine, try clearing the cache and cookies in your browser. This can often help.
Try accessing the Azure Portal using a private or incognito browsing window. This mode doesn't use the existing cookies and cache and can sometimes bypass the issue you're encountering.
Sometimes browser extensions can interfere with web applications. Try disabling extensions, especially those that manage cookies, scripts, or have security functionalities, to see if this resolves the issue.
In some cases, DNS issues can cause problems accessing certain web services. Try changing your DNS settings to a public DNS like Google (8.8.8.8 and 8.8.4.4) or Cloudflare (1.1.1.1).
For operations that do not necessarily require the Azure Portal, consider using the Azure CLI or PowerShell modules. These tools allow you to manage Azure resources directly from your command line and might offer a workaround for your issue.
If the issue persists, consider reaching out to Azure support.