iOS transfer fails - rewards server did not respond - across multiple weeks

I have tried transferring tokens from my iOS wallet to my desktop wallet once a week for the past couple of weeks. I thought there were server issues, based on the message.

What can I do to transfer my tokens?

Why does a crypto wallet run on “reward servers” rather than the blockchain itself?
Shouldn’t we be able to send our own funds from A to B without a rewards server?