user81992: My setup is a little bit complicated and I'm almost sure that my problem is port related.
So I'm running Mac OS X 10.13.4 with Parallels Desktop with a Ubuntu 14.04 VM. I managed to setup bitcoin core in the VM, on top of it I installed c-lightning and managed to fund it with btc (All is happening on the testnet) which I used to open one channel with some random other node. Everything is perfect for now.
Because I want to use the LApp for WordPress Lightning-Publisher I Installed lightning-charge and started an HTTP server running on the default port 9112. All of my ports are correctly forwarded and in my bitcoin.conf file I have allowed all ips. If I run Mozilla in my Ubuntu VM and go to http://api-token:mySecretToken@localhost:9112/info everything is fine, but when I try this on my Mac I get Can't open the page because the server unexpectedly dropped the connection. If I try using my external ip it's the same thing. 
Using several sites to check if my ports are correctly forwarded I get that all corresponding ports are open (18332 for BTC core, 9735 for c-lightning and 9112 for lightning-charge).
Here is my bitcoin.conf

testnet=1
server=1
rpcallowip=0.0.0.0/0
rpcuser=someuser
rpcpassword=somepass

addnode=104.237.131.138
addnode=151.80.205.132
addnode=192.155.82.123
addnode=74.220.255.190
addnode=80.100.203.151

here is my lightning config

network=testnet
alias=IVCHOBIVCHO
port=9735
rgb=008000

Proof that 9112 is open:

Proof that lightning-charge opens from inside the VM:

And in Safari on my mac (using localhost:9112 returns the same error):

Neither Ubuntu, nor my Mac are under any kind of Firewall. My router is TP-Link

user81992: After a lot of research I found the solution to my problem. 
I didn't know this, but in nodejs there's a huge difference if your server runs on 127.0.0.1 and on 0.0.0.0. 
It isn't said in the lightning-charge docs, but except the --port attribute you also have --host which you can set.
Starting lightning-charge with this line charged --api-token mySecretToken --host 0.0.0.0 fixed all of my problems. Gosh was that an unpleasant journey!

81992: <p>My setup is a little bit complicated and I'm almost sure that my problem is port related.</p>

<p>So I'm running Mac OS X 10.13.4 with Parallels Desktop with a Ubuntu 14.04 VM. I managed to <strong>setup bitcoin core</strong> in the VM, on top of it I installed <strong>c-lightning</strong> and managed to fund it with btc (All is happening on the <strong>testnet</strong>) which I used to <strong>open one channel</strong> with some random other node. Everything is perfect for now.</p>

<p>Because I want to use the LApp for WordPress Lightning-Publisher I Installed <strong>lightning-charge</strong> and started an HTTP server running on the default port 9112. All of my ports are correctly forwarded and in my bitcoin.conf file I have allowed all ips. If I run Mozilla in my Ubuntu VM and go to <code>http://api-token:mySecretToken@localhost:9112/info</code> everything is fine, but when I try this on my Mac I get <code>Can't open the page because the server unexpectedly dropped the connection</code>. If I try using my external ip it's the same thing. </p>

<p>Using several sites to check if my ports are correctly forwarded I get that all corresponding ports are open (18332 for BTC core, 9735 for c-lightning and 9112 for lightning-charge).</p>

<p>Here is my bitcoin.conf</p>

<pre>
testnet=1
server=1
rpcallowip=0.0.0.0/0
rpcuser=someuser
rpcpassword=somepass

addnode=104.237.131.138
addnode=151.80.205.132
addnode=192.155.82.123
addnode=74.220.255.190
addnode=80.100.203.151
</pre>

<p>here is my lightning config</p>

<pre>
network=testnet
alias=IVCHOBIVCHO
port=9735
rgb=008000
</pre>

<p>Proof that 9112 is open:
<a href="https://i.stack.imgur.com/LE14R.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/LE14R.png" alt="port open"></a></p>

<p>Proof that lightning-charge opens from inside the VM:
<a href="https://i.stack.imgur.com/FABJ0.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/FABJ0.png" alt="inside VM"></a></p>

<p>And in Safari on my mac (using localhost:9112 returns the same error):
<a href="https://i.stack.imgur.com/OseBW.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/OseBW.png" alt="in safari"></a></p>

<p>Neither Ubuntu, nor my Mac are under any kind of Firewall. My router is TP-Link</p>
 81992: <p>After a lot of research I found the solution to my problem. </p>

<p>I didn't know this, but in nodejs there's a huge difference if your server runs on <code>127.0.0.1</code> and on <code>0.0.0.0</code>. </p>

<p>It isn't said in the lightning-charge docs, but except the <strong>--port</strong> attribute you also have <strong>--host</strong> which you can set.</p>

<p>Starting <strong>lightning-charge</strong> with this line <code>charged --api-token mySecretToken --host 0.0.0.0</code> fixed all of my problems. Gosh was that an unpleasant journey!</p>
