Contact forms going into spam folder

When customers fill out the contact form on our site, the form goes straight into the spam folder in our gmail account. It never used to do this. Is this a WordPress setting or a gmail setting that needs to be changes so that it sends to the inbox rather than the spam folder?

Thanks

You have to read about SPF, DKIM, DMARC, and make proper settings on your domain, from which emails are sent.