I just write down my experience to help someone who have the same trouble with me.
I can not run a full node working properly in Beijing, China, Because my node do not have well access to the seed nodes (sometimes ok, sometimes not).
I had the same problem when I did tests in Tokyo, Beijing, Hong Kong.
go to explorer: https://explorecosmos.network. and find some full node that you can access very well. (usually is the one close to you).
add the address of the node that you picked in step 1 to your persistent_peers in your config.toml.
restart your node.
Good luck. and sorry for my Chinese-English,