Issues sending email in a new installation

Your software
My Mautic version is: v2.16.0
My PHP version is: Version 7.0.33

Your problem
My problem is:

I have been installing Mautic through Softaculous for years and, this has always been going well.
But now I have been installing (in a standard way) the latest version and have been setting up the connection with Amazon SES. All goes well with sending test mails in the configuration tabs (email)

But when I want to send a segment mail, it just stalls and generates an error message

These errors are showing in the log:
[2020-02-26 11:37:11] mautic.WARNING: PHP Warning - require(/home/custoos67/domains/contact.eenlandeensamenleving.nl/public_html/app/cache/prod/doctrine/orm/Proxies/__CG__MauticLeadBundleEntityLead.php): failed to open stream: No such file or directory - in file /home/custoos67/domains/contact.eenlandeensamenleving.nl/public_html/vendor/doctrine/common/lib/Doctrine/Common/Proxy/AbstractProxyFactory.php - at line 209 {“className”:“Mautic\LeadBundle\Entity\Lead”,“classMetadata”:"[object] (Doctrine\ORM\Mapping\ClassMetadata: Doctrine\ORM\Mapping\ClassMetadataInfo@000000001ef99ec900000000365e9c69)",“proxyClassName”:“Proxies\CG\Mautic\LeadBundle\Entity\Lead”,“fileName”:"/home/custoos67/domains/contact.eenlandeensamenleving.nl/public_html/app/cache/prod/doctrine/orm/Proxies/__CG__MauticLeadBundleEntityLead.php"}
[2020-02-26 11:37:11] mautic.WARNING: PHP Warning - require(/home/custoos67/domains/contact.eenlandeensamenleving.nl/public_html/app/cache/prod/doctrine/orm/Proxies/__CG__MauticLeadBundleEntityLead.php): failed to open stream: No such file or directory - in file /home/custoos67/domains/contact.eenlandeensamenleving.nl/public_html/vendor/doctrine/common/lib/Doctrine/Common/Proxy/AbstractProxyFactory.php - at line 209 {“className”:“Mautic\LeadBundle\Entity\Lead”,“classMetadata”:"[object] (Doctrine\ORM\Mapping\ClassMetadata: Doctrine\ORM\Mapping\ClassMetadataInfo@000000001ef99ec900000000365e9c69)",“proxyClassName”:“Proxies\CG\Mautic\LeadBundle\Entity\Lead”,“fileName”:"/home/custoos67/domains/contact.eenlandeensamenleving.nl/public_html/app/cache/prod/doctrine/orm/Proxies/__CG__MauticLeadBundleEntityLead.php"}
[2020-02-26 11:37:11] mautic.ERROR: PHP Notice: require(): Failed opening required ‘/home/custoos67/domains/contact.eenlandeensamenleving.nl/public_html/app/cache/prod/doctrine/orm/Proxies/__CG__MauticLeadBundleEntityLead.php’ (include_path=’.:/opt/alt/php70/usr/share/pear’) - in file /home/custoos67/domains/contact.eenlandeensamenleving.nl/public_html/vendor/doctrine/common/lib/Doctrine/Common/Proxy/AbstractProxyFactory.php - at line 209
[2020-02-26 11:37:11] mautic.ERROR: Symfony\Component\Debug\Exception\FatalErrorException: Notice: require(): Failed opening required ‘/home/custoos67/domains/contact.eenlandeensamenleving.nl/public_html/app/cache/prod/doctrine/orm/Proxies/__CG__MauticLeadBundleEntityLead.php’ (include_path=’.:/opt/alt/php70/usr/share/pear’) - in file /home/custoos67/domains/contact.eenlandeensamenleving.nl/public_html/vendor/doctrine/common/lib/Doctrine/Common/Proxy/AbstractProxyFactory.php - at line 209
[2020-02-26 11:37:11] mautic.CRITICAL: Uncaught PHP Exception Symfony\Component\Debug\Exception\FatalErrorException: “Compile Error: require(): Failed opening required ‘/home/custoos67/domains/contact.eenlandeensamenleving.nl/public_html/app/cache/prod/doctrine/orm/Proxies/__CG__MauticLeadBundleEntityLead.php’ (include_path=’.:/opt/alt/php70/usr/share/pear’)” at /home/custoos67/domains/contact.eenlandeensamenleving.nl/public_html/vendor/doctrine/common/lib/Doctrine/Common/Proxy/AbstractProxyFactory.php line 209 {“exception”:"[object] (Symfony\Component\Debug\Exception\FatalErrorException(code: 0): Compile Error: require(): Failed opening required ‘/home/custoos67/domains/contact.eenlandeensamenleving.nl/public_html/app/cache/prod/doctrine/orm/Proxies/__CG__MauticLeadBundleEntityLead.php’ (include_path=’.:/opt/alt/php70/usr/share/pear’) at /home/custoos67/domains/contact.eenlandeensamenleving.nl/public_html/vendor/doctrine/common/lib/Doctrine/Common/Proxy/AbstractProxyFactory.php:209)"}

Steps I have tried to fix the problem:
Set up a fresh install (multiple times)
Checked the Cron Jobs
Checked Amazon connection
Checked the accessibilities of the used folders on the server.