Microsoft’s Office for the web Visio service is designed to allow teams to work together on diagrams over the web, making it simple to draw flowcharts, to map IT networks, to build organizational charts, or to document business processes. Microsoft lists the start time for this issue as Tuesday, May 21, 2019, with the next update being scheduled for September 6, 2019. The root cause of the problem is a code issue within the latest version of Windows 10, version 1903. Users can use the following procedure as a workaround to resolve the stalling and delay issues if the app stops working.
Source: https://www.bleepingcomputer.com/news/microsoft/windows-10-1903-may-cause-microsoft-visio-to-stall-or-hang/