I have installed bitcoin core on my laptop and I have created a slushpool account. Then I have installed bfgminer on my RPi3 using the following commands:

sudo apt-get install autoconf libtool uthash-dev libjansson-dev libcurl4-openssl-dev libncurses-dev git-core libevent-dev -y
git clone https://github.com/luke-jr/bfgminer.git
cd bfgminer
./autogen.sh
./configure
make

After this, I connected GekkoScience Compac USB Stick Miner to a USB hub and connected that to the USB port of the RPi3. After connecting, I ran bfgminer using the command:

./bfgminer --userpass username.workerID:password --url stratum+tcp://stratum.slushpool.com:3333

But it shows the following errors:

[2019-07-19 12:59:04] Waiting for devices; press 'M+' to add, or 'Q' to quit

[2019-07-19 12:59:04] Probing for an alive pool

[2019-07-19 12:59:07] Pool 0: Unknown stratum msg: {"id":auth,"result":true,"error":null}

Please help me.

I also have another doubt. Its been a few hours and I still do not see any workers in my portal. How long does it take for a worker to show up?

Thanks in advance.