[oscgam1]

Hi, thanks for the response.

The issue is not about sending email (switching providers). The issue is about our customers being able to receive the emails. If we send email to other email clients, they receive the message.

The issue occurs when our customer uses Gmail or any google product. The mail gets classified as spam in those cases.

A good guess is that Google/Gmail maintains their own internal private blocklists, and our domain is most likely on it (even if it is a false positive).