Hello,
our server (outgoing IP 46.28.105.154, WEDOS hosting, Czech Republic) cannot complete a TLS handshake with api.nuki.io (57.129.55.20 / 57.129.72.249). TCP connect succeeds in ~14 ms, but the TLS ClientHello gets no response (timeout after 10 s; tested with TLS 1.2 and 1.3, curl and PHP streams).
The same API works fine from other networks with the same token.
Could you please check whether your firewall/WAF is dropping TLS connections from this IP or IP range?