I had similar issue. See my resolution steps:
1-the bundle type was set to "collection" so I changed to "transaction"
2 -Per recommendation from tulip FHIR chat - I posted to the root FHIR url not /Bundle endpoint
3-I did not have a request object i.e. the HTTP verb POST or PUT. you must add this to your bundle.
I did these three things and now I can GET my patient example using /Patient/1234.