Why did my baker lose a block?

Question

My baker address is tz1XXayQohB8XRXN7kMoHbf2NFwNiH3oMRQQ and I lost the block BMP5PSZ97etLozjnSERt2LLHbPPwNXbAhmNf7WNCWnqkwZHWYXo, and I would like to understand why?

When I check the baker log, I get:

Mar 24 05:07:08 - client.baking: New baking slot found (level 365858, priority 0) at 2019-03-24T10:07:51Z for tezoscat after BL4VioWqcd3A.
Mar 24 05:07:51 - client.baking: No endorsements present in the mempool. Waiting until 2019-03-24T10:08:28Z (37s) for new operations.
Mar 24 05:08:39 - client.baking: Injected block BLExUox6QDgR for tezoscat after BL4VioWqcd3A (level 365858, priority 0, fitness 00::0000000000ad4481, operations 20+0+0+2).

Answer 1

The priority 1 baker (Foundation Baker 5) stole this baking right from you due to its higher fitness (i.e. their block received 2 more endorsements than yours, 33 to 31), as you can see here.

Difficult to say why this happened, as it can have multiple reasons, such as connectivity issues to other nodes, your node's hardware (especially performance of your hard drive), internet speed, etc.

You can see on TzScan that your block is stored in the chain later than the priority 1 block pointing to connectivity issues.