Most email services now contain spam filters. Users can often change the sensitivity of these. It is possible that your emails get classed as spam when they are not.
If particular client(s) complain that your messages go into their spam / junk folder, ask them to check that the settings of their spam filter are appropriate.
Other than the above, there are 2 main reasons why emails sent from Collums might end up in spam / junk folders:
Your email address is a free public service
We strongly recommend that you have an email address that matches the domain of your website. E.g. you@yourwebsite.com
Using a gmail, hotmail etc email address will increase the chance that your emails will be classed as spam.
Your email contains content that is triggering spam filters
Avoid "spammy" language in subject lines e.g. multiple exclamation marks
Avoid unusual or necessary links in your email that could be classed as spam
Read more about how to reduce the chance of you emails going to spam.
TIP : 💡
Ask your clients to add your email address to either a safe sender list or add you to their contacts in their email client of choice for a much more reliable way to ensure they get their emails.