FortiMail Cloud service is a cloud-based email security solution that integrates with Office 365 to provide protection against spam, malware, phishing, data loss, etc. To use FortiMail Cloud service with Office 365, users need to configure both FortiMail Cloud settings and Office 365 settings properly. One possible reason for outgoing emails not reaching the recipients' mailboxes is that the FortiMail access control rules to relay from Office 365 servers public IPs are missing. This means that FortiMail Cloud service does not recognize the Office 365 servers as authorized senders and rejects the outgoing emails. Users need to add the Office 365 servers public IPs to the FortiMail access control rules to allow relaying. Another possible reason for outgoing emails not reaching the recipients' mailboxes is that a Mail Flow connector from the Exchange Admin Center has not been set properly to the FortiMail Cloud FQDN. This means that Office 365 does not route the outgoing emails to the FortiMail Cloud service for scanning and delivery. Users need to create a Mail Flow connector from the Exchange Admin Center and specify the FortiMail Cloud FQDN as the smart host. Reference: https://docs.fortinet.com/document/fortimail-cloud/6.4.0/administration-guide/19662/integrating-fortimail-cloud-with-office-365

To retrieve an SSO group called SalesGroup using the FortiAuthenticator REST API, the following issues need to be fixed in the API call:
The API version should be v2, not v1, as SSO groups are only supported in version 2 of the REST API.
The HTTP method should be GET, not POST, as GET is used to retrieve information from the server, while POST is used to create or update information on the server. Therefore, a correct API call would look like this: curl -X GET -H "Authorization: Bearer <token>" https://fac.example.com/api/v2/sso/groups/SalesGroup Reference: https://docs.fortinet.com/document/fortiauthenticator/6.4.1/rest-api-solution-guide/927310/introduction https://docs.fortinet.com/document/fortiauthenticator/6.4.1/rest-api-solution-guide/927311/sso-groups

The fabric-object-unification setting on FGT_2 is set to local, which means that objects will not be synchronized to any other FortiGate devices in the security fabric. The default setting for fabric-object-unification is default, which means that objects will be synchronized from the root FortiGate to all downstream FortiGate devices.
Since FGT_2 is not the root FortiGate and the fabric-object-unification setting is set to local, objects from the root FortiGate will not be synchronized to FGT_2.
Reference:
Synchronizing objects across the Security Fabric: https://docs.fortinet.com/document/fortigate/6.4.0/administration-guide/880913/synchronizing-objects-across-the-security-fabric

The FortiGate VM is a virtual firewall appliance that can run on various hypervisors, such as ESXi, Hyper-V, KVM, etc. The adapter type for NICs on a FortiGate VM determines the performance and compatibility of the network interface cards with the hypervisor and the physical network. There are different adapter types available for NICs on a FortiGate VM, such as E1000, VMXNET3, SR-IOV, etc. If performance is the main concern and cost is not a factor, one option is to use native ESXi networking with VMXNET3 adapter type for NICs on a FortiGate VM that will run on an ESXi hypervisor. VMXNET3 is a paravirtualized network interface card that is optimized for performance in virtual machines and supports features such as multiqueue support, Receive Side Scaling (RSS), Large Receive Offload (LRO), IPv6 offloads, and MSI/MSI-X interrupt delivery. Native ESXi networking means that the FortiGate VM uses the standard virtual switch (vSwitch) or distributed virtual switch (dvSwitch) provided by the ESXi hypervisor to connect to the physical network. This option can provide high performance and compatibility for NICs on a FortiGate VM without requiring additional hardware or software components. References: https://docs.fortinet.com/document/fortigate/7.0.0/vm-installation-for-vmware-esxi/19662/installing-fortigate-vm-on-vmware-esxi https://docs.fortinet.com/document/fortigate/7.0.0/vm-installation-for-vmware-esxi/19662/networking

VLAN Mode is a more efficient way to connect a FortiExtender to a FortiGate than CAPWAP Mode. This is because VLAN Mode does not require the FortiExtender to send additional control traffic to the FortiGate.
The other options are not correct.
a) Add a switch between the FortiGate and FEX. This will add overhead to the network, as the switch will need to process the traffic.
b) Enable CAPWAP connectivity between the FortiGate and the FortiExtender. This will increase the overhead on the FortiGate, as it will need to process additional control traffic.
d) Add a VLAN under the FEX-WAN interface on the FortiGate. This will not affect the overhead on the FortiGate.