diff --git a/Example/WalletApp/PresentationLayer/Wallet/SessionProposal/SessionProposalInteractor.swift b/Example/WalletApp/PresentationLayer/Wallet/SessionProposal/SessionProposalInteractor.swift
index 477c6f3fa..17d74da18 100644
--- a/Example/WalletApp/PresentationLayer/Wallet/SessionProposal/SessionProposalInteractor.swift
+++ b/Example/WalletApp/PresentationLayer/Wallet/SessionProposal/SessionProposalInteractor.swift
@@ -31,7 +31,7 @@ extension SessionProposalInteractor {
             if let chains = proposalNamespace.chains {
                 accounts = Set(
                     chains.compactMap {
-                        Account($0.absoluteString + ":\(self.accounts[$0.namespace]!)")
+                        Account($0.absoluteString + ":\(self.accounts[$0.namespace] ?? "\($0.namespace)")")
                     }
                 )
                 let sessionNamespace = SessionNamespace(chains: chains, accounts: accounts, methods: proposalNamespace.methods, events: proposalNamespace.events)
diff --git a/Sources/WalletConnectUtils/Extensions/String+CAIPs.swift b/Sources/WalletConnectUtils/Extensions/String+CAIPs.swift
index 433a7e537..2f51d8b4e 100644
--- a/Sources/WalletConnectUtils/Extensions/String+CAIPs.swift
+++ b/Sources/WalletConnectUtils/Extensions/String+CAIPs.swift
@@ -3,7 +3,7 @@ import Foundation
 extension String {
 
     static let chainNamespaceRegex = "^[-a-z0-9]{3,8}$"
-    static let chainReferenceRegex = "^[-a-zA-Z0-9]{1,32}$"
+    static let chainReferenceRegex = "^[-a-zA-Z0-9_]{1,32}$"
     static let accountAddressRegex = "^[a-zA-Z0-9]{1,64}$"
 
     static func conformsToCAIP2(_ string: String) -> Bool {