We have one Teltonika RUT500, Firmware Version RUT5XX_R_01.00.875 that does not connect to the VPN. all other RUT500 are connected to the openVPN. Changing Client certificate and Key etc. doe not help. But Dyndns as a backup works (against our securety Guidelines). All other RUT500 are connected to the VPN. The only difference between the not working one and the others I saw is the firmware version. Is there a known issue with openVPN in this firmware version?
Yes, indeed RUT5XX_R_01.00.875 firmware version has OpenVPN issues. Thank you for reporting this issue to us. We will address this issue in the near future and will let you know once new firmware will be available.