Thank you for posting your question on the Mellanox Community.
Based on the information provided, we cannot determine the root cause of the issue you are experiencing.
As we only support ASAP2 on a limited collection of Operation Systems, please refer to the ASAP2 Release Notes (https://www.mellanox.com/related-docs/prod_software/ASAP2_Hardware_Offloading_for_vSwitches_Release_Notes_v4.4.pdf) to check, in section 1.1 and 1.2 the Software Requirements and Supported Operating Systems.
Also please note:
"In case of offloading VXLAN, the PF should not be added as a port in the OVS data-path but rather be assigned with the IP address to be used for encapsulation."
If you want us to debug this issue further, we recommend to open a Mellanox Support case, by sending an email to firstname.lastname@example.org
Thanks and regards,
~Mellanox Technical Support