Upgrade from 1.6.1.24 to 1.7.6.4 Ajax / Server Error for action upgradeDb

[zsedc]

I still fighting with this problem for two years or more. I want to finally solve it. 

This is the error :

[Ajax / Server Error for action upgradeDb] textStatus: "error " errorThrown:" " jqXHR: "
500 Server Error
Oops, something went wrong.

Try to refresh this page or feel free to contact us if the problem persists.

I see that at the end of 1-click upgrade process. I have tried on different hosting providers, same problem. What should I do? 

Thank you

 

Edited March 31, 2020 by zsedc
just comas (see edit history)