steam has concurrent limit when one andorid device does secondConfirmation?

[stacklesshaha]

hello,should this question be here? if not just delete it. when i use async method to send 50 tradeoffers at the same time,20 tradeoffers make it(STEAM's limit is 5 tradeoffers with the same partner),but when i do androidSecondConfirm using async method,just 1 or 2 secondConfirms make it,the others return "{"success":false}" from steamcommunity.com.
this is my webRequestUrl:
string allowp = SteamGuardAccount.GenerateConfirmationQueryParams("allow");
string allowUrl = $"https://steamcommunity.com/mobileconf/ajaxop?op=allow&{allowp}&cid={data_confid}&ck={data_key}";
does steam have concurrent limit when one andorid device does secondConfirmation? if so,I have to control the concurrent in my code? appropriate for any reply