accuRx is used by healthcare workers such as GPs to send messages to patients.
These messages can be via SMS or email. If you have received an email from your healthcare worker, you will not be able to respond to it like a normal email.
If your healthcare worker needed a response from you, there should be a website link to use to send the response (see screenshot below)
If you are unable to see this link and need to send a response to your healthcare worker, you will need to contact them using your usual methods e.g. phone call.