Lets integrate CWP [Centos WebPanel into WHMCS, its kind of sobber, not tricky nor dificult, just follow the basics and ofcourse have the knowledge for the Networking. 

1. Download the CWP WHMCS module from the link : https://sourceforge.net/projects/cwp-whmcs-setup/files/cwp7 (1).zip
2. Upload on the directory : whmcs/modules/servers/cwp7/cwp7.php [You may need to unzip the folder in the server direcotry which mentioned earlier
3. Once you have that uploaded, you can create the API from the CWP control panel - CWP->CWP Settings-> API Manager
   - Shortname [Your identification name try without space]
   - IP Origin - In this case, use your private IP or Local IP instead of the main shared IP like, 192.168.XX.XX
   - Generate the key code by clicking the generate button at the right 
   - You may have option for the API now, you can select WHMCS for this purpose
   - Format Request - use JSON
   - Now either you can select all or Add,upd, dell, susp, unsp
   Note : Please make sure to open port in TCP/UDP 2304 and may need 2301
4. Now go to WHMCS and setup the server with, 
   - Type [CWP7]
   - Username [root]
   - Password [Your Password]
   - Access Hash [The same key which you have created in step 3
   - Secure [Click the Check Box] Tick to use SSL Mode for Connections
   - Click Save Button
5.  Now you can create the Server group in the WHMCS 
6. Create the product and put the necessary credentials for pricing
7. Go to same products Module Settins - 
   - Select Module Name [Unique Name]
   - Package No: [Go to your CWP panel and package section to get Package ID, 1 is Default
   - Select option - Do not automatically setup this product
   
   

Now, you have successfull integration cwp into whmcs

Note : Please keep in mind to have IP clean or should not be blocked again any restriction.