user51102: If there's one thing I never managed to do: it's comparing strings. 
So I have the incoming message saved here 
String Message2 = IClient[i].readStringUntil('\n');

And every time I try to compare it with
strcmp(Message2.c_str(),"Red"); //Hopefully comparing the Message2 with "Red"

I never get 0 returned.
I know from printing the Message2 to Serial that Message2 contains the word "Red".
I've tried using different methods (string.equal(string2); etc.) but it never said that they are equal. What am I missing out on?

user51102: Found the answer!
After testing around with changing the terminator of the readStringUntil('\n') method it appears that there were leading and trailing white spaces, though not being displayed on the serial monitor they still had an impact on the strcmp(string1, string2) method.
I could solve this problem by "trimming" the received string before comparing it by using the String1.trim(); method. 
In the end looking like:
String Message2 = IClient[i].readStringUntil('\n');

Message2.trim();

strcmp(Message2.c_str(),"Red"); 


51102: <p>If there's one thing I never managed to do: it's comparing strings. 
So I have the incoming message saved here </p>

<pre><code>String Message2 = IClient[i].readStringUntil('\n');
</code></pre>

<p>And every time I try to compare it with</p>

<pre><code>strcmp(Message2.c_str(),"Red"); //Hopefully comparing the Message2 with "Red"
</code></pre>

<p>I never get 0 returned.</p>

<p>I know from printing the Message2 to Serial that Message2 contains the word "Red".</p>

<p>I've tried using different methods (<code>string.equal(string2);</code> etc.) but it never said that they are equal. What am I missing out on?</p>
 51102: <p>Found the answer!</p>

<p>After testing around with changing the terminator of the <code>readStringUntil('\n')</code> method it appears that there were leading and trailing white spaces, though not being displayed on the serial monitor they still had an impact on the <code>strcmp(string1, string2)</code> method.</p>

<p>I could solve this problem by "trimming" the received string before comparing it by using the <code>String1.trim();</code> method. </p>

<p>In the end looking like:</p>

<pre><code>String Message2 = IClient[i].readStringUntil('\n');

Message2.trim();

strcmp(Message2.c_str(),"Red"); 
</code></pre>
