The status "LmtByPLmt" means that the inverter is limiting the output power because of how the Export Power setting has been configured. If this status is being shown, that means the inverter is limiting it's output power as to not export any energy to the grid. Basically, the inverter is saying that it could be generating more energy if you allowed it to do so. If your goal is to be set up for minimum export, then this status is an indication that the inverter is doing what it should be doing.
However, if your goal is for the system to be exporting excess PV power to the utility, you will need to change Export Power setting. Please see the article Export Power Set and FailSafe Configuration on how to set up your system for maximum export or whatever it is that you need.