Axios GET gets error 500, but it's not logged

[olsy]

I built a custom uptime checker for a website using node and axios and I struggle to figure out why one URL returns 500, while it opens in browser just fine.
I also can not find error 500 in the OLS logs.

 

[Cold-Egg]

Was the 500 returned by LSWS/OLS? And the result is 200 via curl command?

 

[olsy]

I only have OLS web server (no proxy) on that web site.
It seems that wget from the uptime checker's container is also getting 500, but I still can't find the error logged.

 

[olsy]

I thought I had it when I switched the checked URL to www, it stopped receiving the 500 for some time, but now after 20 minutes it started returning 500 as well.
Could this all be part of DDOS defense? I'm pinging the same 5 URLs on the checked site with interval of 10 seconds. But that wouldn't explain why 4 other URLs return 200, and no problem in browser.

 

[Cold-Egg]

No problem

 

[olsy]

Would LSWS cache plugin also cache a request from axios? Would it cache a 500 response?

 

[olsy]

Conclusion: I really need to start writing tests for my WP projects.
The wp_remote_post call returned WP_Error, and I was only ready for response.