Some emails are not being received when trying to email forms

Some recipients are not receiving the emails with the link to the forms we are sending. I have tried sending to my personal email and work email and my personal email is a hotmail account and the email with the link was received in my spam folder after a few minutes. However, my work email is with Yahoo and the email sent was not received in either my inbox or my spam folder. Another co-worker sent it to her personal gmail account and the email was never received in either the inbox or her spam folder. Could you please investigate?

Thank you!