That's the same issue I have with my LNbits routed by nginx, some can zap, some cannot (mostly Primal cannot).
i've build myself a little proxy for nostr:npub1qkdmqs7sqazsk3swa7ymvhq7g0j4fuxk06sxr395qsaw9kngvjus37h9tf (although someone told me he couldn't zap me, others can, not sure that was temporary)
Discussion
nostr:npub1de6l09erjl9r990q7n9ql0rwh8x8n059ht7a267n0q3qe28wua8q20q0sd couldn't zap me, he seems to be using nostr:npub1jluy3twvf338v6zlujzzdhjkzjy8ezj34ksydr8vw8a6jwp89ygshpp2kq — no problems with zaps from nostr:npub12vkcxr0luzwp8e673v29eqjhrr7p9vqq8asav85swaepclllj09sylpugg (i remember at least one that worked)
95% sure you have a CORS issue with the "dalliard.ch" endpoint: 
that doesn't look right — will take a look
Can you check if I have the same issue on eluc@bitcoincoin.ch LN address ?
you would need to set that as your lightning address in your nostr profile in order to test it properly
I just set it back to eluc@bitcoincoin.ch if you had a minute to test.
it worked for both of us, but would be great if nostr:npub1jluy3twvf338v6zlujzzdhjkzjy8ezj34ksydr8vw8a6jwp89ygshpp2kq could confirm with the client he had the cors issue (at least with my address)
yes looks like it works.... looks like you are in French-speaking Switzerland?
I've got great memories of summer in https://en.wikipedia.org/wiki/Les_Diablerets here
Nice resort. Did ski there for a long time.
with a cors issue like this, some clients will be able to zap, but some will not
to demo the failure, you can set up a separate nostr account and attempt a zap from a web client like Yakhonne or Nostrudel
ah it is about the client and not the lightning provider beeing used. cause i got two zaps from you, i guess not from yakhonne or nostrudel?
yes, CORS is something enforced by web browsers... very confusing...