Oh well they don't support bunker urls, only nip05 (which could be resolved to bunker url if only your signer had a domain name...)
Discussion
Interesting. I'll investigate...
Yes, this is it. I quickly threw up blackcoffee@nostr.cymru as a NIP5 (https://nostr.cymru/.well-known/nostr.json?name=blackcoffee) and it works swimmingly!
CC nostr:npub18ams6ewn5aj2n3wt2qawzglx9mr4nzksxhvrdc4gzrecw7n5tvjqctp424
Only user@nsec.app is supported at this time. It's not clearly explained and should be. Sorry.
I thought so too but with nostr:npub1xdtducdnjerex88gkg2qk2atsdlqsyxqaag4h05jmcpyspqt30wscmntxy s help I added support for this