I've been getting "Validation Failed. Not a valid payment request" errors for weeks, now. I get get zaps, but not send them.
Discussion
If nostr:npub1h2qfjpnxau9k7ja9qkf50043xfpfy8j5v60xsqryef64y44puwnq28w8ch, you might have to re-pair service with nostr. They had a little publicized issue that requires it. Prob lost a ton of users at least for sending.