OG Metatags not working

[gXLg]

I own a subdomain <name>.ddns.net and have a TLS/SSL certificate by letsencrypt.
The webpage at that address is a normal html site, which has opengraph meta tags. I have put all the same tags as I did on my github pages site (gxlg.github.io/index.html).
The difference: sending the github link to discord shows the expected embed, my ddns site link - not.

Additional information:
I host the page using node.js and https module.
When logging the requests, I can see, that discordbot2.0 visits the page to crawl for metatags, but still none are sent to the chat.

[night]

In general OpenGraph scraping can fail when:

• the server is blocking us
• we've been captcha'd because the server thinks we're a bot (which we are)
• we've been IP blocked
• the server is not using a supported version/cipher for TLS**
• the page is not returning valid OpenGraph metadata (if it's an HTML page, not a direct image/video link): https://ogp.me/
• the direct image/video link has content which is too large to embed

** Supported Cipher Suites

// TLS1.3 suites
TLS13_CHACHA20_POLY1305_SHA256
TLS13_AES_256_GCM_SHA384
TLS13_AES_128_GCM_SHA256

// TLS1.2 suites
TLS12_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
TLS12_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
TLS12_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
TLS12_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
TLS12_ECDHE_RSA_WITH_AES_256_GCM_SHA384
TLS12_ECDHE_RSA_WITH_AES_128_GCM_SHA256

[gXLg]

still not working