Found this article "The Sleep States of the ESP8266" here: https://blog.creations.de/?p=149
Learned the default sleep mode is "Auto Modem Sleep." I believe this is the source of my problem.
Power is not an issue on my project; so I used the following:
extern "C" {
#include "user_interface.h"
}
void loop() {
wifi_set_sleep_type(NONE_SLEEP_T);
delay(100);
//rest of loop code
}
Testing this solution; faster page loading, with no timeout error messages --so far. Will continue to observe over the next few days.
William