Which desktop browser? I can't replicate the key error on Chrome, FF, or Safari. The provided key should be valid. Can you run `console.log(VAPID_PUBLIC_KEY)` in the devtools?
On iOS, signing is inherently tricky. Apple doesn't like PWAs, which is what nsec.app is, so your best bet is probably going to be a remote signer. Can you log in with nsec.app from a different device?
On keychat, I can't help you there, it looks like the browser they build in doesn't have service worker/push manager support. nostr:nprofile1qy2hwumn8ghj7un9d3shjtnyv9kh2uewd9hj7qgwwaehxw309ahx7uewd3hkctcpr9mhxue69uhhyetvv9ujuumwdae8gtnnda3kjctv9uq3wamnwvaz7tmjv4kxz7fwdehhxarj9e3xzmny9uq36amnwvaz7tmwdaehgu3wvf5hgcm0d9hx2u3wwdhkx6tpdshsqg9mly364yjxqe0c33qv0kdlv8xvcrlnlnlsvk5vktl5e7akyzy0rcd9whra?
