Assuming that you or someone knows for sure this motor SHOULD be able to accelerate that conveyor, and assuming that by saying "the OL trips on the drive" that you know what the trip code is, and it is motor overload, then it must be something else. Too aggressive of an acceleration ramp profile as suggested already is a district possibility, but not being able to accelerate even unloaded makes that unlikely, unless maybe the belt is too tight.
One other really common mistake that causes symptoms like this, is that you have a 230/460V motor, and someone connected it for 230V, not 460V, but the output from the drive is based on 460V. What happens is, the motor saturates almost immediately because the V/Hz ratio is double what it should be. So then it is drawing more current than it should, but because most of that current is now just heating up the windings instead of doing useful work, it cannot produce enough torque to accelerate the load. At 27Hz, the VFD is likely attempting to limit current by limiting speed, which is how it does that, but it's not working because of the motor misconnection, so eventually the VFD has to protect the motor and trip.
If by chance this is an IEC motor that is set up for 400Star/230Delta, something like that, then you would connect it in Star for 460V.