Hi Milorad,
Please see below sample code for 60 days duration that you can try in test environment. I recommend you have all your authentication and identity provider settings backed up in separate file in case you run into a problem and need to re-configure manually.
In my tests the sample didn't cause any issues with existing auth config, however, I didn't perform extensive testing.
$containerAppName = "mycontainerapp"
$resourceGroupName = "myresourcegroup"
$cookieTTL = "60.00:00:00"
$authConfig = Get-AzContainerAppAuthConfig -AuthConfigName current -ContainerAppName $containerAppName -ResourceGroupName $resourceGroupName
$params = @{AuthConfigName="current";ContainerAppName=$containerAppName;ResourceGroupName=$resourceGroupName;CookieExpirationConvention="FixedTime";CookieExpirationTimeToExpiration=$cookieTTL}
$authProps = @("ForwardProxyConvention","ForwardProxyCustomHostHeaderName","ForwardProxyCustomProtoHeaderName","GlobalValidationExcludedPath","GlobalValidationRedirectToProvider","GlobalValidationUnauthenticatedClientAction","HttpSettingRequireHttps","IdentityProvider","LoginAllowedExternalRedirectUrl","LoginPreserveUrlFragmentsForLogin","NonceExpirationInterval","NonceValidateNonce","PlatformEnabled","PlatformRuntimeVersion","RouteApiPrefix","RouteLogoutEndpoint")
$authProps|ForEach-Object -Process {if ($authConfig.$_ -ne $null) {$params.Add($_.ToString(),$authConfig.$_)}}
New-AzContainerAppAuthConfig @params
Please click Accept Answer and upvote if above was helpful.
Thanks.
-TP