Dell Precision 5690 will not connect to Wi-Fi or keeps disconnecting

The checks in more detail

Try the 5 GHz band by name, forget the network and rejoin, restart the router and test on a phone hotspot. Dell Optimizer's network features can prioritize apps and change behavior, so turn them off for a test. On a managed laptop, a VPN or a security agent can drop the connection. A Network reset in Windows rebuilds the adapters. If Wi-Fi and Bluetooth both fail, the card may be faulty and Dell should replace it under warranty.

If the wireless adapter works but the speed is far below the router's rating, check the Wi-Fi channel width and band the laptop negotiated in the adapter's status, and consider that the laptop's antennas sit in the display lid so that a half-closed lid or an external monitor arrangement can shield them. Run a speed test beside the router first to see the best the laptop can do. Dell's SupportAssist can scan the network adapter and offer a driver repair, and Windows' Network adapter troubleshooter resets the stack; both are quick to run and leave a clear result to quote to support.

Keep a note of the driver version and date, because Dell lists known issues against specific releases. Because the 5690 is a workstation, it often runs a corporate VPN client and a security agent that hook into the network stack, and an outdated VPN client is a frequent cause of drops that look like Wi-Fi faults. Disconnect the VPN and watch the connection for an hour; if it holds, update the VPN client or ask IT for a newer one. Packet loss can be checked with a continuous ping to the router, which shows whether drops hit the local link or the wider network.