I wanted to try Okay CMS but haven't managed to do so

I have just installed Wordpress Woocommerce, OpenCart and Drupal Comerce, everything went pretty smooth so far.
I also wanted to install okay cms and I hanged at step two.
At Step One I got green light from the installer that my shared hosting is okay, but then at install/?route=Step_2 my server responded with 504 Gateway Time-out nginx/1.14.1
Do you have any idea why this could happen?

I can go back on step one, where I get

But then I can not proceed further. Can you help me debug this?
In the error log I get this

2021/06/24 18:09:32 [error] 4093817#4093817: *303719382 upstream timed out (110: Connection timed out) while reading response header from upstream, client: 194.187.154.252, server: ok.wihola.com, request: "GET /install/?route=Step_2 HTTP/1.1", upstream: "http://127.0.0.1:8080/install/?route=Step_2", host: "ok.wihola.com", referrer: "http://ok.wihola.com/install/"
2021/06/24 18:10:52 [error] 4093817#4093817: *303719382 upstream timed out (110: Connection timed out) while reading response header from upstream, client: 194.187.154.252, server: ok.wihola.com, request: "GET /install/?route=Step_2 HTTP/1.1", upstream: "http://127.0.0.1:8080/install/?route=Step_2", host: "ok.wihola.com"
2021/06/24 18:11:03 [error] 4093820#4093820: *303720976 upstream timed out (110: Connection timed out) while reading response header from upstream, client: 194.187.154.252, server: ok.wihola.com, request: "GET /install/ HTTP/1.1", upstream: "http://127.0.0.1:8080/install/", host: "ok.wihola.com"
2021/06/24 18:12:33 [error] 4093820#4093820: *303720976 upstream timed out (110: Connection timed out) while reading response header from upstream, client: 194.187.154.252, server: ok.wihola.com, request: "GET / HTTP/1.1", upstream: "http://127.0.0.1:8080/", host: "ok.wihola.com"