I think I got it. The problem is Cloudflare, because when I try to curl fetch this page, I get the same 403 error
$ curl --head https://community.cloudflare.com/t/403-using-curl/490150 HTTP/2 403 date: Wed, 29 Mar 2023 14:00:52 GMT content-type: text/html; charset=UTF-8 cross-origin-embedder-policy: require-corp cross-origin-opener-policy: same-origin cross-origin-resource-policy: same-origin permissions-policy: accelerometer=(),autoplay=(),camera=(),clipboard-read=(),clipboard-write=(),fullscreen=(),geolocation=(),gyroscope=(),hid=(),interest-cohort=(),magnetometer=(),microphone=(),payment=(),publickey-credentials-get=(),screen-wake-lock=(),serial=(),sync-xhr=(),usb=() referrer-policy: same-origin x-frame-options: SAMEORIGIN 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 set-cookie: __cf_bm=AcNfbEmgpCMIAMbu2O505XNXymHPYK6L93KcxICcqUQ-1680098452-0-ASZhf8NpCD4MHPuZRlBj3un34/LEzqoMfVuGwaAUIJdyPe0RSo1b+JxCmP6B7yuICDAjCk8saFjW6PwyS54XfzEBh3dzk0arH3omO1rWC5vv; path=/; expires=Wed, 29-Mar-23 14:30:52 GMT; domain=.community.cloudflare.com; HttpOnly; Secure; SameSite=None report-to: {"endpoints":[{"url":"https:\/\/a.nel.cloudflare.com\/report\/v3?s=ZQIkDM%2BDuNAaPCm8t42zhyip7%2BDo5uX29IGcF7MxJ4U3uk2aVUQPsSfBuW4zzlzeeWmjfn%2FFYvA6xNeUrKNW4bQjCQNVvc2kHK%2BWtudRPRGlboVdZx7RnJ0tyuZP7t52kzy0AvnyIRQd3A%3D%3D"}],"group":"cf-nel","max_age":604800} nel: {"success_fraction":0,"report_to":"cf-nel","max_age":604800} strict-transport-security: max-age=2592000 server: cloudflare cf-ray: 7af8a43fef50904f-FRA alt-svc: h3=":443"; ma=86400, h3-29=":443"; ma=86400