Yes, it's interesting what the cause is!
Discussion
yes this is a problem on the end of whoever you are trying to zap -- if u provide their lightning address we can test it on our end and see if we can find the problem
I don't know their addresses, but I tested with my other wallet at rubenstorm@blink.sv and it had an error. When I made a invoice with the same wallet it worked. I used yakihonne, let me test from Alby Go with Rizful
From Alby go it worked

i was just able to send 10 sats to rubenstorm@blink.sv from a Rizful vault
Yes it came... Why did I had the error!
I was also able to zap you.

Thanks, I keep an eye on it if it happens again! With what client did you zap?
Alright yes. I zapped with YakiHonne
Same I did when it had an error. But I have a theory about that problem. If my theory is right, it has nothing with YakiHonne or any nostr client, wallet to do.
Yeah, sometimes the responsible node can have some issues that will cause such problem.
My theory is different. I am not in Africa anymore, am now in Germany and I think my internet jumps off. It doesn't show me, but I think it is on and off ... Last night I tried updating my phone, it failed due to "Download not completed"
Maybe Germany has worse internet than Africa 🤣