Your pool should be able to provide more details. Are you solo mining on the pool?
What is the pay and denomination schedule of the pool? Depending on your hash rate, it could take a very long time (maybe never) for you to receive a reward.
The error: [RPC0] WARN wallet.wallet2 src/wallet/wallet2.cpp:660 Transaction extra has unsupported format: I have received this using MiningCore .net pool software - there are numerous forks available, but all fairly similar.
I have recieved this warning whilst operation two open source mining clients (cpu miner and cpu stak) for testing for many days now without a coin in the Wallet via Monero gui. I have confirmed that 'shares' are being accepted from miner to pool and all deamons are functioning.
I under stand this is 'Just a warning' but after so many days I feel like this is the cause. (Other than I'm not running hardly any miners currently, yes I'm aware I require a good percentage of block chain in the future.)
Thanks for any leads, hopefully this helps others I'm using the latest build: 'monero-gui-v0.11.1.0' - all local host for now.