I had the same problem and I searched everywhere but did not find the solution.
I created new App on Playgrounds and looked into the "Package.swift" file in the root folder of the App using "Show Package Contents" by right clicking on Playgrounds project folder.
On comparing I found that "resources" tag was missing from targets. I added resources tag and assigned the "Resources" folder name and that fixed the issue.
targets: [
.executableTarget(
name: "AppModule",
dependencies: [
.product(name: "Lottie", package: "lottie-ios")
],
path: ".",
resources: [
.process("Resources")
]
)
]
Check if following code is missing from targets in "Package.swift" file.
resources: [
.process("Resources") ]