To improve sluggish performance of your Apple Airport router, have a look at these points -
Upgrade your Apple Airport router
Open AirPort Utility for iOS. The app will check for updates automatically when opened and will tell you if any of your devices have an update available. To install the update, select your Apple Airport router and click "update". Now just update your Apple Airport router.
Figure out frequency
In general, the lower the frequency, the more powerful the signal is. If you have walls, a refrigerator or a major obstruction between the router and the device you're trying to use, then 2.4 GHz tends to be very good.
Surf the channels
Launch the AirPort Utility on your Mac while connected to your AirPort Express or AirPort Extreme.Click on your AirPort Express or AirPort Extreme on the main screen. Click on the Wireless tab in the top navigation. On the next screen, click on Wireless Options. Select a different channel than what you're currently on. Next, click on Save.
Lower RTS threshold
By lowering RTS threshold values, you can improve Apple Airport router's speed even if there is any interference.
Use WPA 2 security as encryption
For security's sake, it's always wise to protect your wireless network with a password. When setting it up, there are multiple security options to choose from, but as it pertains to your network's performance, there's only one: WPA2 security. This is because WPA2 uses an advanced encryption standard that's only available on the fastest wireless internet networks.
Still experiencing any error then call at Apple Router Technical Support Number.