I try using the live link but no pictures or error message as:
Too many Connections! the tunnel session ‘number’ has violated the rate-limit policy of 20 connections per minutes by initiating 103 connections in the last 60 seconds. Please decrease your inbound connection (i can’t see how !) or upgrade to a paid plan for additionnal capacity.
The erro encountered was: ERR_NGROK_702
Does it mean that with a paid account this problem will be solved ?
With a paid account you will be able to load additional assets without issues - however - have a look at this answer given by Clay. He briefly explains how Ngrok handles connections and requests.
In summation - It is a limitation of Ngroks free tunnel service.
The title mentions CSS, but it affects all assets that are loaded in the browser.