I had the same issue. I am using Magento 2.4.4
I resolved this issue. You just need to use
{{block class="Magento\Newsletter\Block\Subscribe" name="home.newsletter" template="footer.phtml"}}
instead of
{{block class="Magento\Newsletter\Block\Subscribe" name="home.newsletter" template="subscribe_form_footer.phtml"}}
Because Ebizmarts_MailChimp uses footer.phtml template
edit this file: public_html/app/design/frontend/Smartwave/porto/Smartwave_Porto/layout/default.xml
replace line 14 with this
