At Apple they continue to work on the different versions of their OS and in the case of the Apple Watch a few weeks ago we saw how Walkie-Talkie stopped working from one day to the next due to a security problem, Apple had it disabled. This is a function that came with the watchOS 5 version and with it users can send voice messages just as we do with one of these devices.
So by clicking on the button once you have this function activated and between Series 4 watch models, it is possible to send voice messages from one user to another. In this case, the problem was one of security and quite important since third parties could listen to the messages despite not being sent directly to us. That's why Apple left Walkie-Talkie disabled until the problem was solved and it seems that now they have already done so.
And the function is once again operational for Series 4 owners. It is true that the Cupertino company may have problems of this type with their applications or tools, and it is shown that they have them with these cases, as demonstrated how quickly they get to work on it to fix the problem.
Actually I know few people in my environment who are constantly using this Walkie-Talkie function, but as we always say it has to work perfectly for those who use it, even if only a few people. In this case, the best of all is that it seems that everything is solved and the failure is solved with a small update to watchOS 5. that you will find in the iPhone settings, in Watch> General> Software update.