Cannot convert null literal to non-nullable reference type.

Cannot convert null literal to non-nullable reference type.

This async method lacks 'await' operators and will run synchronously. Consider using the 'await' operator to await non-blocking API calls, or 'await Task.Run(...)' to do CPU-bound work on a background thread.

This async method lacks 'await' operators and will run synchronously. Consider using the 'await' operator to await non-blocking API calls, or 'await Task.Run(...)' to do CPU-bound work on a background thread.

Possible null reference argument for parameter 's' in 'double double.Parse(string s)'.

Possible null reference argument for parameter 'uniqueKey' in 'JwtSecurityToken JwtHelper.GetJwtToken(string username, string uniqueKey, string issuer, string audience, TimeSpan expiration, Claim[] additionalClaims = null)'.

Possible null reference argument for parameter 'issuer' in 'JwtSecurityToken JwtHelper.GetJwtToken(string username, string uniqueKey, string issuer, string audience, TimeSpan expiration, Claim[] additionalClaims = null)'.

Possible null reference argument for parameter 'audience' in 'JwtSecurityToken JwtHelper.GetJwtToken(string username, string uniqueKey, string issuer, string audience, TimeSpan expiration, Claim[] additionalClaims = null)'.

Dereference of a possibly null reference.