Sketch runs only once after upload

During development of a sketch for internet radio on ESP8266 and Nextion display I compile and upload without problems, the program starts to run and communicates with the display. As soon as I reset the ESP the program does not start at all. I have seen a similar problem on this forum, but do not remember where and when. Anyone knows?
Of course I can copy my sketch, but it is fairly long and not completed yet, far from that to be honest..

When you load the sketch to the ESP8266, the device is automatically reset.
You say it works. When you do a manual reset later (pressing the reset button on the esp8266 ? ) it does not work. Is that right ?
Have you anything connected to GPIO pins 0,2 or 15 ?

Correct, after a manual reset it won’t run and yes, I connected to port 2.. what is the problem there?

pin #2 can't be low at boot time: A Beginner's Guide to the ESP8266

6v6gt,
Thanks! I will test! That is a super introduction to the ESP by the way, thanks for sharing!

Middelbh:
. . . That is a super introduction to the ESP by the way, thanks for sharing!

I agree. The author of that document is on this forum. PieterP.

He claims it here in post #1: Arduino projects Wi-Fi connectivity - best ratio "easy to setup and use"/cost - Project Guidance - Arduino Forum

6v6gt,

The problem seems to be caused by my SPIFF settings! I used 3mb SPIFF, but now I setit to 1Mb and all works. Thanks for your help,