Response from Server RE: Contact Form lost emails

It recently came to light that I havn’t been receiving all my enquiries via the contact form on my website, I checked the log on the contact form and 5 didn’t come through in January. After raising this with my server this was their response.

“It appears that some of the forms are being stopped as spam in our filter. Our 2nd line team located 40-50 messages, most of which have been released and sent on, any others have been identified as spam and remained trapped. I would suggest looking at the coding of the form as it may be that this needs to be adjusted to stop the filter from believing this is spam”

Does anyone know what “adjusting the coding” means in respect of this. I havn’t changed anything and it was working absolutely fine until recently.