That means they have no idea what to make of some of the emails you're sending.
Consider a note that says, "Call me when you get a chance." You know your motivation is to check in and see how your team member is coping with the work from home dynamic, but they don't know that unless you tell them. And until they know what the conversation is about, they're likely to jump to conclusions and stress out over the all the possible things you want to talk about because it's human nature to jump to the worst-case scenario.
Clarity is kindness, especially when sending emails in a work from home setting.
This is just one of the things to consider when communicating with remote teams. Download the the FREE e-book Communicating With Remote Teams for more tips. If you're interested in sharing these conversation strategies with your entire team, email [email protected] for virtual training options.