Why email deliverability is becoming a serious issue for charities
For many charities and membership organisations, email remains one of the most important ways to stay in touch with supporters. Newsletters, event invitations, campaigns and fundraising appeals all depend on it.
But over the last few years, something has been quietly changing. Emails that used to arrive reliably are now landing in spam folders, disappearing completely, or being blocked by receiving mail servers.
This is known as the deliverability problem, and it is becoming increasingly common.
If your organisation relies on email to communicate with supporters, it is something worth paying attention to.
What deliverability actually means
Deliverability is simply the ability for an email to successfully reach a recipient’s inbox. This sounds easy but when you send a mailing, several things can happen:
- the email reaches the inbox
- the email is placed in a spam folder
- the email is rejected by the receiving mail server (bounced)
- the email is silently filtered and never seen again
Modern email systems make these decisions automatically based on the reputation of the sender, the quality of the mailing list, and technical configuration. The challenge is that these checks are becoming more strict all the time and often it’s hard to see what’s changing.
Email providers are tightening their filters
Email service providers (ESPs) such as Gmail, Microsoft Outlook, Yahoo and Apple Mail process billions of emails every day. A large proportion of these are spam, phishing attempts or malicious messages and to protect their users, providers have steadily increased the sophistication of their filtering systems.
Recent changes include:
- stronger domain authentication requirements (SPF, DKIM and DMARC)
- reputation scoring for sending domains
- machine learning systems that detect spam patterns
- stricter limits on bulk email senders
Large providers have also introduced policies that specifically target bulk email senders who do not maintain clean mailing lists. For legitimate organisations this can sometimes feel frustrating, but these measures exist because the scale of spam and phishing is just so enormous.
The problem of ageing mailing lists
One of the most common deliverability issues we see is simply old mailing lists. Over time, email addresses can become invalid for a range of reasons:
- people change jobs or organisations
- domains expire or are no longer maintained
- mailboxes are abandoned
- organisations merge or restructure
If a mailing list hasn’t been cleaned for several years, it can contain a large number of addresses that no longer exist. When emails are repeatedly sent to invalid addresses, the receiving servers start to treat the sender as unreliable. This can reduce the chance that future emails reach the inbox.
Contacts who don’t interact
Another common issue is large numbers of contacts who haven’t opened or clicked links in an email for a long time. From a deliverability perspective, engagement matters. Email providers track whether recipients interact with messages. When a mailing list contains many inactive contacts, it can signal that the messages are not really wanted.
Over time this can lead to more messages being filtered or deprioritised. For many organisations this happens unintentionally. Contacts accumulate over years of events, campaigns and imports, but the list is never reviewed and those contacts don’t unsubscribe, they can just move or ignore what is ending up in their spam folder.
The hidden risk of spam traps
Occasionally we encounter something more serious: spam trap addresses.
Spam traps are so-called honeypot email addresses used by internet service providers and anti-spam organisations to identify senders who are not following good mailing practices.
They are created not for genuine communication, but rather to lure spam. These addresses are typically only published in a location hidden from general view so an e-mail address harvesting bot (used by spammers) can find it but it wouldn’t ever be passed to a legitimate sender.
If a mailing system sends to a spam trap, it can significantly damage the sender’s reputation. In severe cases the sending server or domain may be blocked entirely. This is one of the reasons most email providers strongly discourage purchased or scraped mailing lists.
If they didn’t actively opt in to your list, you probably shouldn’t be sending mail to them.
Technical configuration matters too
Even with a good mailing list, technical configuration plays an important role. Modern email systems expect domains to be correctly authenticated using:
- SPF records
- DKIM signing
- DMARC policies
These help receiving servers confirm that the email is genuinely authorised by the sending organisation. If these settings are missing or misconfigured, emails are more likely to be rejected or filtered.
Why this matters for charities
For charities and membership organisations, deliverability problems have real consequences. If emails don’t reach supporters: event attendance may drop, fundraising campaigns may underperform and volunteers or members may miss important updates
Often the organisation can be unaware anything is wrong. The mailing appears to send successfully, but fewer people actually receive or read it and over time this can undermine communication efforts that rely heavily on email.
Good email practice makes a difference
The good news is that deliverability can usually be improved with a few sensible practices:
maintain a clean mailing list
- remove inactive contacts periodically
- ensure proper domain authentication
- avoid purchased or scraped lists
- monitor bounce and complaint rates
Email providers want legitimate organisations to reach their audiences. Following recognised best practices helps demonstrate that your organisation is a responsible sender.
A shared responsibility
Deliverability is not just a technical issue. It sits at the intersection of technology, data management and communication practice. When organisations take care of their mailing lists and infrastructure properly, email continues to be one of the most effective and affordable ways to communicate with supporters. But as filtering systems become more advanced, it is increasingly important to treat email as a managed communication channel rather than something that simply runs in the background.
Make sure someone is paying attention to how things run. Write engaging and useful content. And remove old or unresponsive contacts from your list.
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