user91279: I have setup WooCommerce and BTCpayserver in Google cloud, and synced. Test to buy with BTC seems to work.
Adding Lightning fails:
I modified in BTCpay Lightning nodes in the Store management 
"clicking here" added the connection string:
Type=clightning;server=unix://etc/lightning_bitcoin/lightning-rpc

I submit and came back to test connection, it fails:
Error: Error while connecting to the lightning node via 34.73.111.47:9735 (The operation was canceled.)operation was canceled.)

I used during setup the following Exports:
 export BTCPAY_HOST="btcpay.elmit.com" 
 export NBITCOIN_NETWORK="mainnet"
 export BTCPAYGEN_CRYPTO1="btc"
 export BTCPAYGEN_REVERSEPROXY="nginx"
 export BTCPAYGEN_LIGHTNING="clightning"
 export BTCPAYGEN_ADDITIONAL_FRAGMENTS="opt-save-storage-xs;opt-save-memory" 
 export BTCPAYGEN_ADDITIONAL_FRAGMENTS="$BTCPAYGEN_ADDITIONAL_FRAGMENTS;opt-add-woocommerce"
 export WOOCOMMERCE_HOST="store.elmit.com"

Did I miss something?

user91279: I found it. The port 9735 is not open to the public. 
Go to google cloud console
Home -> VPC network -> Firewall rules

+ Create firewall rule:

Name      Type    Targets   Filters          Protocols / ports  Action  Priority    Network
lightning Ingress Apply to all  IP ranges: 0.0.0.0/0 tcp:9735       Allow   1000        default


91279: <p>I have setup WooCommerce and BTCpayserver in Google cloud, and synced. Test to buy with BTC seems to work.</p>

<p>Adding Lightning fails:
I modified in BTCpay Lightning nodes in the Store management 
"clicking here" added the connection string:</p>

<pre><code>Type=clightning;server=unix://etc/lightning_bitcoin/lightning-rpc
</code></pre>

<p>I submit and came back to test connection, it fails:</p>

<pre><code>Error: Error while connecting to the lightning node via 34.73.111.47:9735 (The operation was canceled.)operation was canceled.)
</code></pre>

<p>I used during setup the following Exports:</p>

<pre><code> export BTCPAY_HOST="btcpay.elmit.com" 
 export NBITCOIN_NETWORK="mainnet"
 export BTCPAYGEN_CRYPTO1="btc"
 export BTCPAYGEN_REVERSEPROXY="nginx"
 export BTCPAYGEN_LIGHTNING="clightning"
 export BTCPAYGEN_ADDITIONAL_FRAGMENTS="opt-save-storage-xs;opt-save-memory" 
 export BTCPAYGEN_ADDITIONAL_FRAGMENTS="$BTCPAYGEN_ADDITIONAL_FRAGMENTS;opt-add-woocommerce"
 export WOOCOMMERCE_HOST="store.elmit.com"
</code></pre>

<p>Did I miss something?</p>
 91279: <p>I found it. The port 9735 is not open to the public. </p>

<p>Go to google cloud console</p>

<pre><code>Home -&gt; VPC network -&gt; Firewall rules

+ Create firewall rule:

Name      Type    Targets   Filters          Protocols / ports  Action  Priority    Network
lightning Ingress Apply to all  IP ranges: 0.0.0.0/0 tcp:9735       Allow   1000        default
</code></pre>
