A contact form has two halves. The half you can see shows a thank-you page. The half you cannot see sends an email. They fail separately, and the visible half almost never breaks.
So a form can be broken for months while every visitor sees "Thanks, we will be in touch." Nothing on your site looks wrong. Your inbox just goes quiet, and quiet is easy to explain away as a slow season.
Here is how to find out. It takes ten minutes.
It arrived, in the inbox, at every address. Good. Put the test on the calendar for the first of every month. Forms do not stay fixed. Plugins update, passwords expire, mail providers change their rules, and none of them tell you.
It arrived in spam. Customers' messages are landing there too, and some of them have been deleted unread. Whoever manages your email needs to allow-list the sending address, and whoever built the site needs to check how the form sends mail. Sending "from" the customer's own address is the usual cause.
It arrived at one address and not the other. Find out which address people were actually relying on. Then fix the list.
It did not arrive. The form has been quietly dropping every submission since the last thing that changed on the site or the mail account. Nobody did this to you. It is what happens when a credential expires or a plugin updates and there is no test in place to catch it. Call whoever built the site today, not next week, and ask them to look at the mail log rather than the form settings. The settings will look fine.
Before you spend another dollar sending people to a page, know that the page can reach you. Ten minutes a month, and you will never again wonder whether the quiet weeks were the market or the form.
This test is the first thing we run on every site we take on, before any money goes to traffic. How lead tracking works