Php ssh2 extensions are installed normally, but cannot connect to the target host

{Code ...} the above is my code. The platform I use is lnmp, And the ssh2 extension has been installed normally, because no error is reported using the ssh2_connect function, and I also ensure the Host IP address and user name, the password is correct, but two consecutive errors are output, that is, on the connect host...

$link=ssh2_connect($host,22);if(!$link){echo"error";}$link1=ssh2_auth_password($link,$user,$pwd);if(!$link1){echo"error";}

The above is my code. The platform I use is lnmp, And the ssh2 extension has been installed normally, because no error is reported using the ssh2_connect function, and I also ensure the Host IP address and user name, the password is correct, but two errors are still output consecutively. That is to say, an error has occurred while connecting the host. Where is the error? Is it because the supporting software required by ssh2 is not installed?
Please explain how to install the lnmp Platform)

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$link=ssh2_connect($host,22);if(!$link){echo"error";}$link1=ssh2_auth_password($link,$user,$pwd);if(!$link1){echo"error";}

The above is my code. The platform I use is lnmp, And the ssh2 extension has been installed normally, because no error is reported using the ssh2_connect function, and I also ensure the Host IP address and user name, the password is correct, but two errors are still output consecutively. That is to say, an error has occurred while connecting the host. Where is the error? Is it because the supporting software required by ssh2 is not installed?
Please explain how to install the lnmp Platform)

Ask how to install ssh2 extension on the lnmp Platform

I also have this problem, but I don't know if it solves it.