Michail1

That will allow you to compile; however, the library is still obsolete until it is updated to use coinmarketcap pro/basic plan. Meaning, you have to create an account and use...

The code has not been updated except that of Json to version 6. What ticker do you have? If AFKdata, you could update to their code for free. There is...

The solution is to go back to ArduinoJson version 5.x.x which will allow you to compile; however, this library is obsolete anyway and you can no longer use coinmarketcap version...

This library is obsolete. The problem is not ArduinoJson. The problem is coinmarketcap killed version 1. The library must be changed to supply an API key (version 2).

I am pretty sure (almost guaranteed) that you are using a new M5stack board version which causes the problem. Meaning, I think you are likely using an updated board version...