1. All miners cannot connect to the same pool port

That is because the pool port is disabled, please check whether it is disabled by yourself or by the network itself, and in the latter case, you can only give up the pool port to use other pool ports.

2. Part of miners cannot connect to the pool

That is due to pool port usage is up to the limit, and the miner will automatically change to the second pool port, which does not affect normal mining.

3. All miners cannot connect to the pool

   a. Check whether the network connection is normal

   b. Consult whether the mining pool is normal