Wamp x64 не будет работать с php 5.6.16

Я установил WAMP 3, 64-битную версию, которая поставляется с PHP 7 и PHP 5.6.16.

Дело в том, что он работает только с версией 7, но не с версией 5.6.16.

Если у меня версия 7, я могу нормально открыть localhost, если я переключаюсь на версию 5.6, там написано: «Этот сайт недоступен».
Журнал ошибок Apache:

[Fri Jul 08 18:59:42.721292 2016] [mpm_winnt:notice] [pid 8776:tid 652] AH00428: Parent: child process 8788 exited with status 255 -- Restarting.
[Fri Jul 08 18:59:42.859839 2016] [auth_digest:notice] [pid 8776:tid 652] AH01757: generating secret for digest authentication ...
[Fri Jul 08 18:59:42.936418 2016] [mpm_winnt:notice] [pid 8776:tid 652] AH00455: Apache/2.4.17 (Win64) PHP/5.6.16 configured -- resuming normal operations
[Fri Jul 08 18:59:42.936418 2016] [mpm_winnt:notice] [pid 8776:tid 652] AH00456: Apache Lounge VC14 Server built: Oct 11 2015 11:49:07
[Fri Jul 08 18:59:42.936418 2016] [core:notice] [pid 8776:tid 652] AH00094: Command line: 'C:\\wamp64\\bin\\apache\\apache2.4.17\\bin\\httpd.exe -d C:/wamp64/bin/apache/apache2.4.17'
[Fri Jul 08 18:59:43.007482 2016] [mpm_winnt:notice] [pid 8776:tid 652] AH00418: Parent: Created child process 5336
[Fri Jul 08 18:59:43.647394 2016] [auth_digest:notice] [pid 5336:tid 420] AH01757: generating secret for digest authentication ...
[Fri Jul 08 18:59:43.728167 2016] [mpm_winnt:notice] [pid 5336:tid 420] AH00354: Child: Starting 64 worker threads.
[Fri Jul 08 18:59:45.162617 2016] [mpm_winnt:notice] [pid 8776:tid 652] AH00428: Parent: child process 5336 exited with status 255 -- Restarting.
[Fri Jul 08 18:59:45.368338 2016] [auth_digest:notice] [pid 8776:tid 652] AH01757: generating secret for digest authentication ...
[Fri Jul 08 18:59:45.436406 2016] [mpm_winnt:notice] [pid 8776:tid 652] AH00455: Apache/2.4.17 (Win64) PHP/5.6.16 configured -- resuming normal operations
[Fri Jul 08 18:59:45.436406 2016] [mpm_winnt:notice] [pid 8776:tid 652] AH00456: Apache Lounge VC14 Server built: Oct 11 2015 11:49:07
[Fri Jul 08 18:59:45.436406 2016] [core:notice] [pid 8776:tid 652] AH00094: Command line: 'C:\\wamp64\\bin\\apache\\apache2.4.17\\bin\\httpd.exe -d C:/wamp64/bin/apache/apache2.4.17'
[Fri Jul 08 18:59:45.534501 2016] [mpm_winnt:notice] [pid 8776:tid 652] AH00418: Parent: Created child process 7404
[Fri Jul 08 18:59:46.217823 2016] [auth_digest:notice] [pid 7404:tid 156] AH01757: generating secret for digest authentication ...
[Fri Jul 08 18:59:46.276887 2016] [mpm_winnt:notice] [pid 7404:tid 156] AH00354: Child: Starting 64 worker threads.

Что может быть причиной?