Connection not open on send when subscribing to new block headers

Question

I am running a local ethereum node with the below configuration

geth --syncmode "full" --datadir "." --ethash.dagdir "." --cache=4096 --rpc --rpcaddr test.example.com --rpcapi="web3,miner,admin,db,net,eth,personal,debug,txpool" --rpccorsdomain "test.example.com" --rpcvhosts "test.example.com" --ws --wsaddr test.example.com --wsapi="web3,miner,admin,db,net,eth,personal,debug,txpool" --wsorigins "*"

I am listening to new block headers by subscribing to blockchain events. I am using web socket connection.

web3 version 1.2.4

let Web3 = new web3('wss://test.example.com/');

subscription fails after sometimes it is throwing Error connection not open on send()

Please provide any suggestions or workaround for this issue. Thanks in advance