A method performed by a network node for enabling root cause analysis in across a plurality of network systems, the method comprising: receiving update information of a first local root cause analysis mechanism of a first network operator from a plurality of network operators; generating , based on the update information, a new node to be added to a global root cause decision tree, wherein the global root cause decision tree is to be shared by at least two of the plurality of network operators; requesting storage of the new node in a distributed ledger that is shared by the plurality of network operators, wherein a set of one or more policies for a plurality of network operators are stored in the distributed ledger; participating in a verification operation of the new node; responsive to determining that the verification operation is successful, adding an entry including the new node to the distributed ledger as part of the global root cause decision tree; receiving , from a requestor, a request for a root cause analysis, wherein the request includes an operator identifier, an input, and an expected output; retrieving , based on the input and the expected output, one or more entries from the distributed ledger; reconstructing one or more global root cause decision trees from the entries; determining , based on the set of one or more policies for the plurality of network operators, whether the request for the root cause analysis can be fulfilled by accessing the one or more global root cause decision trees for a network operator identified with the operator identifier; responsive to determining that the request can be fulfilled, performing a root cause analysis based on the one or more global root cause decision trees and the input received in the request, and transmitting a result of the root cause analysis to the requestor; and responsive to determining that the request cannot be fulfilled, transmitting a denied access response to the requestor. receiving update information of a first local root cause analysis mechanism of a first network operator from a plurality of network operators; generating , based on the update information, a new node to be added to a global root cause decision tree, wherein the global root cause decision tree is to be shared by at least two of the plurality of network operators; requesting storage of the new node in a distributed ledger that is shared by the plurality of network operators, wherein a set of one or more policies for a plurality of network operators are stored in the distributed ledger; participating in a verification operation of the new node; responsive to determining that the verification operation is successful, adding an entry including the new node to the distributed ledger as part of the global root cause decision tree; receiving , from a requestor, a request for a root cause analysis, wherein the request includes an operator identifier, an input, and an expected output; retrieving , based on the input and the expected output, one or more entries from the distributed ledger; reconstructing one or more global root cause decision trees from the entries; determining , based on the set of one or more policies for the plurality of network operators, whether the request for the root cause analysis can be fulfilled by accessing the one or more global root cause decision trees for a network operator identified with the operator identifier; responsive to determining that the request can be fulfilled, performing a root cause analysis based on the one or more global root cause decision trees and the input received in the request, and transmitting a result of the root cause analysis to the requestor; and responsive to determining that the request cannot be fulfilled, transmitting a denied access response to the requestor. <EOS>