Modify your web.config code as shown below:
<configuration>
<connectionstrings>
<add name="MySqlConnection" providername="System.Data.SqlClient">
connectionString="Server=mssql.world19.server-world.net;Database=micro ;Uid=x123; Pwd=y123" />
</add></connectionstrings>
<system.web>
<!-- AUTHENTICATION -->
<authentication mode="Forms">
<forms loginurl="login.aspx" name=".ASPXFORMSAUTH" />
</authentication>
<!-- AUTHORIZATIONN -->
<authorization>
<deny users="?" />
</authorization>
<membership defaultprovider="AspNetSqlMembershipProvider" userisonlinetimewindow="15">
<providers>
<clear />
<add name="AspNetSqlMembershipProvider">
type="System.Web.Security.SqlMembershipProvider, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"
connectionStringName="MySqlConnection"
enablePasswordRetrieval="false"
enablePasswordReset="true"
requiresQuestionAndAnswer="true"
applicationName="/"
requiresUniqueEmail="false"
passwordFormat="Hashed"
maxInvalidPasswordAttempts="5"
minRequiredPasswordLength="7"
minRequiredNonalphanumericCharacters="1"
passwordAttemptWindow="10"
passwordStrengthRegularExpression="" />
</add></providers>
</membership>
<profile>
<providers>
<clear />
<add name="AspNetSqlProfileProvider" connectionstringname="MySqlConnection" applicationname="/">
type="System.Web.Profile.SqlProfileProvider, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
</add></providers>
</profile>
<rolemanager>
<providers>
<clear />
<add name="AspNetSqlRoleProvider" connectionstringname="MySqlConnection" applicationname="/">
type="System.Web.Security.SqlRoleProvider, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
<add name="AspNetWindowsTokenRoleProvider" applicationname="/">
type="System.Web.Security.WindowsTokenRoleProvider, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
</add></add></providers>
</rolemanager>
</system.web>
</configuration>