user46538: I'm using Arduino Uno and ESP8266 in a project.
I'm using AT Commands to connect to wi-fi and make a request. I'm using the monitor serial to test the code before compile it in arduino.
It is connecting to wi-fi and I can make a request to a server in my network but when i try to make a request to my web-service in cloud it doesn't work well.
The return is an HTML with an 404 page instead of what I am expecting:
<h1>Hello Versa</h1>

Here is my code:
AT+CIPSTART="TCP","ternary.com.br",80
AT+CIPSEND=18
GET /webservice/

Can someone help me telling me what I am doing wrong?

After see the answer of Maximilian Gerhardt, I solved it writing the following sequence in the monitor serialize:
AT+CIPSTART="TCP","ternary.com.br",80
AT+CIPSEND=70
GET /webservice/ HTTP/1.1
Host: ternary.com.br
Connection: Close
[Just press enter and send a new line]


user30175: A HTTP requests is comprised of more than just GET /webservice/. Take a look at what curl (console-line HTTP client) does.
C:\>curl -v "http://ternary.com.br/webservice/"
*   Trying 187.84.237.200...
* Connected to ternary.com.br (187.84.237.200) port 80 (#0)
> GET /webservice/ HTTP/1.1
> Host: ternary.com.br
> User-Agent: curl/7.46.0
> Accept: */*
>
< HTTP/1.1 200 OK
< Date: Fri, 11 May 2018 15:04:16 GMT
< Server: Apache
< X-Powered-By: PHP/5.6.30
< Vary: Accept-Encoding
< Cache-Control: max-age=0, no-cache, no-store, must-revalidate
< Expires: Wed, 11 Jan 1984 05:00:00 GMT
< X-UA-Compatible: IE=Edge,chrome=1
< Pragma: no-cache
< Transfer-Encoding: chunked
< Content-Type: text/html; charset=UTF-8
<
<h1>Hello Versa</h1>* Connection #0 to host ternary.com.br left intact

You will have to at least transfer the minimal correct HTTP Headers of the form
GET /webservice/ HTTP/1.1
Host: ternary.com.br
Connection: Close

To get an answer. Also mind the ending \r\n\r\n. Refer to this website for more headers.
When I only send GET /webservice/ I also get 404 page.
C:\>cat test
GET /webservice/

C:\>cat test | ncat ternary.com.br 80
[...]
        <title data-i18n="[html]404_page.title">404 ÔÇô P├ígina n├úo encontrada</title>


46538: <p>I'm using Arduino Uno and ESP8266 in a project.</p>

<p>I'm using AT Commands to connect to wi-fi and make a request. I'm using the monitor serial to test the code before compile it in arduino.</p>

<p>It is connecting to wi-fi and I can make a request to a server in my network but when i try to make a request to my web-service in cloud it doesn't work well.</p>

<p>The return is an HTML with an 404 page instead of what I am expecting:</p>

<pre><code>&lt;h1&gt;Hello Versa&lt;/h1&gt;
</code></pre>

<p>Here is my code:</p>

<pre><code>AT+CIPSTART="TCP","ternary.com.br",80
AT+CIPSEND=18
GET /webservice/
</code></pre>

<p>Can someone help me telling me what I am doing wrong?</p>

<hr>

<p>After see the answer of Maximilian Gerhardt, I solved it writing the following sequence in the monitor serialize:</p>

<pre><code>AT+CIPSTART="TCP","ternary.com.br",80
AT+CIPSEND=70
GET /webservice/ HTTP/1.1
Host: ternary.com.br
Connection: Close
[Just press enter and send a new line]
</code></pre>
 30175: <p>A HTTP requests is comprised of more than just <code>GET /webservice/</code>. Take a look at what <code>curl</code> (console-line HTTP client) does.</p>

<pre><code>C:\&gt;curl -v "http://ternary.com.br/webservice/"
*   Trying 187.84.237.200...
* Connected to ternary.com.br (187.84.237.200) port 80 (#0)
&gt; GET /webservice/ HTTP/1.1
&gt; Host: ternary.com.br
&gt; User-Agent: curl/7.46.0
&gt; Accept: */*
&gt;
&lt; HTTP/1.1 200 OK
&lt; Date: Fri, 11 May 2018 15:04:16 GMT
&lt; Server: Apache
&lt; X-Powered-By: PHP/5.6.30
&lt; Vary: Accept-Encoding
&lt; Cache-Control: max-age=0, no-cache, no-store, must-revalidate
&lt; Expires: Wed, 11 Jan 1984 05:00:00 GMT
&lt; X-UA-Compatible: IE=Edge,chrome=1
&lt; Pragma: no-cache
&lt; Transfer-Encoding: chunked
&lt; Content-Type: text/html; charset=UTF-8
&lt;
&lt;h1&gt;Hello Versa&lt;/h1&gt;* Connection #0 to host ternary.com.br left intact
</code></pre>

<p>You will have to at least transfer the minimal correct HTTP Headers of the form</p>

<pre><code>GET /webservice/ HTTP/1.1
Host: ternary.com.br
Connection: Close
</code></pre>

<p>To get an answer. Also mind the ending <code>\r\n\r\n</code>. Refer to <a href="https://www.tutorialspoint.com/http/http_header_fields.htm" rel="nofollow noreferrer">this website</a> for more headers.</p>

<p>When I only send <code>GET /webservice/</code> I also get 404 page.</p>

<pre><code>C:\&gt;cat test
GET /webservice/

C:\&gt;cat test | ncat ternary.com.br 80
[...]
        &lt;title data-i18n="[html]404_page.title"&gt;404 ÔÇô P├ígina n├úo encontrada&lt;/title&gt;
</code></pre>
