In brief
animation-name connects an element to a named @keyframes rule. If the name matches no available rule, the browser has no corresponding sequence of styles to run.
Useful to know
animation-name connects an element to a named @keyframes rule. If the name matches no available rule, the browser has no corresponding sequence of styles to run. [1]
For a motionless indicator, first check the exact name. Increasing duration will not create missing keyframes. Multiple names can describe separate animations applied together.
Sources
For further detail and to check the information: