Chat and messages are down, I have been trying all day!!
This seems to come and go for some users, and is fortunately quite rare. You could try the following:
1) deleting your browser cache
2) using a different browser (you can run different browsers on a phone or tablet - eg Chrome, Firefox, or Opera)
3) rebooting the device
4) using a different device
5) using this link: https://knowndonorregistry.com/mykdr/messages
None of those may work though, then it may just fix itself by tomorrow, and we don't know why.
If you could tell us your device, browser, and what happens when you try to send a message (including any error message, and if possible, a screenshot), that would help us investigate.
If there's someone you need to reach urgently, then I could pass your contact details onto them.