Gmail rejects our emails

We had this issue earlier this year but got it resolved. Here is the email I received from you at that time: 

Typically, I would make these changes for you, but unfortunately, your nameservers are not pointing to Homestead, so we don't have control over your DNS. Please log into your hosting company and update the DNS records for email to match the records in this article:

‎DNS Records for Homestead Email | Homestead Community

If you don't know how to update DNS on their system, you would have to reach out to that hosting company for guidance. 

We then had our hosting company update the DNS records and everything worked fine up until late yesterday when the gmail rejections started again. Is there anything you can assist with or let us know what we need to do please?