You can know more about blocks on this site: https://bitcoin.org/en/developer-guide#block-broadcasting

From the word orphan itself, it means having no parent so they can't be validated therefore are not real, spendable because the staking reward for that block was already given out on the block that reached consensus.

To put it simple,  the blocks are split in two. One is remove from the chain while the other one continues. On your case, you're on the former.

This should happen occasionally.Just keep on  staking/mining, you'll get lucky soon.

Good luck!