On Friday, Signal faces a Global Outage after Millions of Downloads, users were not able to send any messages from both Mobile and its Dekstop application. The company posted a tweet where they said " Signal is experiencing technical difficulties. We are working hard to restore service as quickly as possible".
We have been adding new servers and extra capacity at a record pace every single day this week nonstop, but today exceeded even our most optimistic projections. Millions upon millions of new users are sending a message that privacy matters. We appreciate your patience.
— Signal (@signalapp) January 15, 2021
They said soon all the services will be back online you don't have to worry they are going to add more servers so in the future this won't happen again. Soon we will be able to use Signal again without any more issues.