When trying to connect on Devolutions Server from Remote Desktop Manager or through the web Ui, you can get the following error in the Devolutions Server logs.
SecurityTokenInvalidIssuerException - IDX10205: Issuer validation failed. Issuer: 'System.String'. Did not match: validationParameters.ValidIssuer: 'System.String' or validationParameters.ValidIssuers: 'System.String'.
at Microsoft.IdentityModel.Tokens.Validators.ValidateIssuer(String issuer, SecurityToken securityToken, TokenValidationParameters validationParameters)
at System.IdentityModel.Tokens.Jwt.JwtSecurityTokenHandler.ValidateTokenPayload(JwtSecurityToken jwtToken, TokenValidationParameters validationParameters)
at System.IdentityModel.Tokens.Jwt.JwtSecurityTokenHandler.ValidateToken(String token, TokenValidationParameters validationParameters, SecurityToken& validatedToken)
at Devolutions.Server.Handler.OAuthHelper.LoginWithOAuth(String bearerToken)
Solution
The problem may result from an invalid Access URI string with an extra '/' at the end of the URL. Ensure to set it properly according to this article Access URI.