For pages which have a lot of data and thus requiring more time, you can change some settings, so AMP can finish processing the page.
To fix it, youll need to access the hidden configuration page in Firefox. Just type about:config in the address bar and youll get a page full of hidden configurations.
In the Filter box, type dom.max_script_run_time. This will narrow the options till only the dom.max_script_run_time option remains. Right-click it and choose Modify. A box pops up. Change the number to something bigger like 20. This is the maximum time a script can run before Firefox considers it unresponsive.
If you cant find the string in the about:config page, create it by right-clicking anywhere and then choose New> Integer and enter dom.max_script_run_time. When prompted for the value, use 20.
As for max_chrome_script_run_time, change that setting to 30.