Recently, we are using the Phalcon 3.3 framework, the local environment is wampserver, and php7.0 is selected. It is found in the project that using curl to request other interfaces of the project or other interfaces of the project report errors. If you switch to php5.6, you can request normally. After trying many methods, you can't solve it. It suddenly occurred to me that Apache uses its own PHP module by default. Would it be for this reason. Then try to run Apache switch in fastcgi mode.
The error reported is:

Error: Access to undeclared static property: Phalcon\Di::$_default in D:\wamp\www\myphalcon\config\services.php on line 35

This is using Apache's default php module

Here's how to switch:
1. Download fastcgi module, open https://www.apachelounge.com/download/ Choose the corresponding VC version to download. I compiled it with VC14, so I chose the VC14 version
2. After downloading and decompressing, copy the mod_fcgid.so file to the Apache installation path modules directory
3, Open the configuration file httpd.conf and add the following code

LoadModule   fcgid_module modules/mod_fcgid.so
<IfModule fcgid_module>
    FcgidIOTimeout 60
    FcgidConnectTimeout 30
    FcgidMaxProcesses 8
    FcgidOutputBufferSize 64
    ProcessLifeTime 240
    FcgidMaxRequestsPerProcess 500
    FcgidMinProcessesPerClass 0

    Options ExecCGI
    AddHandler fcgid-script  .php 
    #php installation directory of your project
    FcgidWrapper "D:/wamp/bin/php/php7.0.23/php-cgi.exe" .php
</IfModule>

At this time, you need to restart Apache to complete the switch
However, I have configured the virtual host, so I have to make changes to the virtual host
4. Original virtual host configuration

<VirtualHost *:80>
     ServerName myphalcon.com
     ServerAlias myphalcon.com
     DocumentRoot "${INSTALL_DIR}/www/myphalcon/public"
     <Directory "${INSTALL_DIR}/www/myphalcon/public/">
       Options +Indexes +Includes +FollowSymLinks +MultiViews
       AllowOverride All
       Require local
     </Directory>
</VirtualHost>

After the change (ExecCGI is the options just configured)

<VirtualHost *:80>
     ServerName myphalcon.com
     ServerAlias myphalcon.com
     DocumentRoot "${INSTALL_DIR}/www/myphalcon/public"
     <Directory "${INSTALL_DIR}/www/myphalcon/public/">
       Options Indexes FollowSymLinks Includes ExecCGI
       AllowOverride All
       Require local
     </Directory>
</VirtualHost>

5. Restart Apache

Use curl again to access this project or other local project interfaces, and you can access it normally