What is the "keep alive taking too long to send" error indicating? Since yesterday I am encountering WiFi drop outs with my Airport Express.
I'm on Mountain Lion 10.8.5 and have a 1st generation A1264 Airport Express.

The drop outs are mainly noticeable as the music over Airplay is interrupted.
In the console I see the following error that repeats itself every drop out:

13/11/16 3:01:51.527 PM coreaudiod[274]: 2016-11-13 03:01:51.527435 PM [AirPlay] ### Keep alive taking too long to send (5 seconds)
13/11/16 3:01:55.136 PM coreaudiod[274]: 2016-11-13 03:01:55.135959 PM [AirPlay] *** Sent futile retransmit to 10.0.1.1:6001 for seq 31771, latest 32840 (1 total)
13/11/16 3:01:55.138 PM coreaudiod[274]: 2016-11-13 03:01:55.137672 PM [AirPlay] *** Sent futile retransmit to 10.0.1.1:6001 for seq 31772, latest 32840 (2 total)
13/11/16 3:01:55.138 PM coreaudiod[274]: 2016-11-13 03:01:55.138033 PM [AirPlay] *** Sent futile retransmit to 10.0.1.1:6001 for seq 31773, latest 32840 (3 total)


I have restarted my laptop and my Airport Express, but the errors keep appearing.

When I monitor the throughput of my WiFi signal I see the following (screenshot shows 2 drop outs):


What might be causing this issue? And how can I diagnose this further?
I have "solved" the issue by factory resetting my Airport Express.
This does seem a bit of a sledgehammer approach, so everyone is still welcome to post a real solution.