If there is not enough resources to allow Zowe, Z/OSMF, and Endevor starting quickly enough, connections can fail because of timeout.
Error message about timeout json file not found is issued in the log:
ZWES1038I Server timeouts file '/x/xxx/zowe/instance/svwinst1_25_0.0/workspace/app-server/serverConfig/timeouts.json' either not found or invalid JSON. ZSS sessions will use the default length of one hour.
Then
z/OSMF connection attempt timed out and the gateway shutdown:
ZWEAGW1:Thread-9:33620386> ZWESVUSR ERROR (o.z.a.g.s.s.JwtSecurity) ZWEAG108E z/OSMF instance 'zOSMF' not found or incorrectly configured. Gateway is shutting down.
Release : 3.0
Component : BRIGHTSIDE ZOWE ZOS
Add or Increase the timeout value for Z/OSMF connection: