DispatchQueue.main.async {     /// do your action inside main thread (here) }

thanks for your replay i'm working on ios and get my certificate from api and i will aply this polices var policies =  SecPolicyCreateSSL(true, host as CFString) SecTrustSetPolicies(serverTrust, policies) after that i will run SecTrustEvaluateWithError(serverTrust, &error) but some time the execution of SecTrustSetPolicies(serverTrust, policies) will be complete after the execution of SecTrustEvaluateWithError(serverTrust, &error) so it will give me error because the police didn't applied before evaluation how to fix that