Katie,
One of my first posts in the Community a few years ago was an article about navigating email delivery into China, this can be a more challenging region to deliver to. This article gives high level guidance: Navigating email delivery into China
Marketo takes sending into China very seriously and it is one of the regions we monitor closely. If an unexplained drop in delivery rates occurs we investigate quickly. We have "tuned" the sending speeds into Chinese networks to that we are sending as quickly as possible without aggravating their filters or inbound email networks.
I do recommend sending from a dedicated IP if you have the email volume to support that. When you send from a dedicated IP we are able to negotiate with providers like qq.com for whitelisting. This allows customers to send higher volumes into qq.com than customers sending from our shared IPs. If you are already on an IP please reach out to Marketo Support and ask them to escalate you to Marketo's Email Deliverability Team so we can negotiate this whitelisting on your behalf. If you are interested in discussing a dedicated IP reach out to your CSM to initiate that discussion, they will likely get someone from my team in a meeting to talk this through with you.
At the end of the day most of the same email best practices apply when sending into China: permission is very important so that people expect your email and will not complain, removing non-responders over time to keep your email sends to an active an engaged audience is important and ensuring that your email content drives further engagement so people are opening your email and navigating to your site and establishing a direct relationship with your brand. All of these will send signals to the Chinese email networks that your email is wanted and should be delivered to their customer's inboxes because you are driving engagement.
If you are having any other specific issues, let us know. We may be able to escalate to the network you are seeing issues with or do our own troubleshooting to understand and explain the drivers behind issues you are seeing.
Thank you,
Kiersti
Kiersti Esparza, CIPP/US | Director, Email Privacy & Deliverability | Marketo, Inc,
PS - Thank you @Josh Hill for highlighting this for me!