Error when trying to add a page/post in WP

I searched and couldnt find the help under 520 error. wp-admin is fine and i can go through a few pages but when i try create a new post this morning it shows json error and then now i cant edit or add a post.
Yesterday it was fine and working perfectly, what changed? (no settings changed). Below is the copy and paste and i went into the links, paused cloudflare then got an origin error. Ran the 16kb test via chatgpt and it was under, not sure how to fix this:

Web server is returning an unknown error Error code 520

2024-05-10 23:17:55 UTC

You

Browser

Working

Tokyo

Cloudflare

Working

startuphack.tech

Host

Error

What happened?

There is an unknown connection issue between Cloudflare and the origin web server. As a result, the web page can not be displayed.

What can I do?

If you are a visitor of this website:

Please try again in a few minutes.

If you are the owner of this website:

There is an issue between Cloudflare’s cache and your origin web server. Cloudflare monitors for these errors and automatically investigates the cause. To help support the investigation, you can pull the corresponding error log from your web server and submit it our support team. Please include the Ray ID (which is at the bottom of this error page). [Additional troubleshooting resources]

i ran a few curls and chatgpt said it was ok but told me to provide the below:

HTTP/1.1 520
Date: Fri, 10 May 2024 23:29:40 GMT
Content-Type: text/plain; charset=UTF-8
Content-Length: 15
Connection: keep-alive
Report-To: {“endpoints”:[{“url”:“https://a.nel.cloudflare.com/report/v4?s=D3e7P6FkBz3zBfzjbFx5OhuD0ALvthg7W3CxMg7PKlLnrm60S4fB7E8z9mz3N40C1HmmB10OTkamAiOxl3XLv30SW5PNSinC1Zf3M2yuKOYTpo85FfM%2BYYT8MHVc3j4v7sN%2F”}],“group”:“cf-nel”,“max_age”:604800}
NEL: {“success_fraction”:0,“report_to”:“cf-nel”,“max_age”:604800}
X-Frame-Options: SAMEORIGIN
Referrer-Policy: same-origin
Cache-Control: private, max-age=0, no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Expires: Thu, 01 Jan 1970 00:00:01 GMT
Server: cloudflare
CF-RAY: 881db5b5add5e01d-NRT
alt-svc: h3=“:443”; ma=86400

  1. Verbose cURL Command Output:
*   Trying 104.21.23.223:443...
* Connected to startuphack.tech (104.21.23.223) port 443
* schannel: disabled automatic use of client certificate
* ALPN: curl offers http/1.1
* ALPN: server accepted http/1.1
* using HTTP/1.1
> GET /wp-admin/ HTTP/1.1
> Host: startuphack.tech
> User-Agent: curl/8.4.0
> Accept: */*
>
* schannel: remote party requests renegotiation
* schannel: renegotiating SSL/TLS connection
* schannel: SSL/TLS connection renegotiated
< HTTP/1.1 520
< Date: Fri, 10 May 2024 23:30:35 GMT
< Content-Type: text/plain; charset=UTF-8
< Content-Length: 15
< Connection: keep-alive
< Report-To: {"endpoints":[{"url":"https:\/\/a.nel.cloudflare.com\/report\/v4?s=c6BLSUyNreyQWzgdiJwVVJCtcHFJESDaU5oyVjtN0TkySDNMUltrvBl%2BHwrQYu3ojJh1ViW90zT9UnJ19MmJXjDAO1MOoCa%2B%2F2kWI265ouIXPheNaaCFM5hO%2FJDgDr0N7XfD"}],"group":"cf-nel","max_age":604800}
< NEL: {"success_fraction":0,"report_to":"cf-nel","max_age":604800}
< X-Frame-Options: SAMEORIGIN
< Referrer-Policy: same-origin
< Cache-Control: private, max-age=0, no-store, no-cache, must-revalidate, post-check=0, pre-check=0
< Expires: Thu, 01 Jan 1970 00:00:01 GMT
< Server: cloudflare
< CF-RAY: 881db70e0e628a5a-NRT
< alt-svc: h3=":443"; ma=86400
<
error code: 520* Connection #0 to host startuphack.tech left intact

now it is working fine? WHy does this drop in and out depending on time?