.Net Core 3.0
续：Error unprotecting the session cookie.The payload was invalid. 出现了新的BUG
warn: Microsoft.AspNetCore.Session.SessionMiddleware[7] Error unprotecting the session cookie. System.Security.Cryptography.CryptographicException: The key {40d34e51-8e22-41b3-a179-fe353bcd0280} was not found in the key ring. at Microsoft.AspNetCore.DataProtection.KeyManagement.KeyRingBasedDataProtector.UnprotectCore(Byte[] protectedData, Boolean allowOperationsOnRevokedKeys, UnprotectStatus& status) at Microsoft.AspNetCore.DataProtection.KeyManagement.KeyRingBasedDataProtector.DangerousUnprotect(Byte[] protectedData, Boolean ignoreRevocationErrors, Boolean& requiresMigration, Boolean& wasRevoked) at Microsoft.AspNetCore.DataProtection.KeyManagement.KeyRingBasedDataProtector.Unprotect(Byte[] protectedData) at Microsoft.AspNetCore.Session.CookieProtection.Unprotect(IDataProtector protector, String protectedText, ILogger logger)
把浏览器关闭再打开，就可以了。
Error unprotecting the session cookie.The key {...} was not found in the key ring.
原文：https://www.cnblogs.com/vipsoft/p/13049879.html