Contact Form stopped working

Hello,
On one of my websites includes a few forms (a contact form, a testimonial form, and a FAQ form). All were working fine since the website was launched. However, my client reached out to me today requesting that I check the forms because she did not receive several form notifications recently that were sent out from her website. She also ran a TEST form from her site and did not receive it either.

I, too, sent out several test forms from the site from each of the forms. Everything looks like it is going through correctly. After submitting the form, I get the appropriate "Thank You" message, and all the submittals are showing in the FORM Submissions backend list. The FAQ and Testimonial forms are going through to the email listed, however the CONTACT forms (which are the most critical) are not going through to the listed emails. The SUBMIT button has the appropriate email(s) listed. I can't figure out what the problem is and why these 2 contact forms just stopped working.

Thank you,
Anna