Beckett oil burner lock out

Oil burners are not a DIY appliance -- I'd suggest a competent tech.

Not much to do for simple diy, since it's running (ie, you have power, oil and the thermostat works).
Has it been cleaned/serviced recently ? Do you get black smoke out of the chimney while it's running ?

If it has a primary that contains a cad cell self-check, you could utilize that to check cad cell resistance.
On mine, I start the burner and wait a bit for things to stabilize, press the reset button once. The light will flash a number of times to represent the resistance of the cad cell. 4 flashes means replace the cell, 3 is getting marginal but ok, 2 and 1 are good.

Not to overstate the obvious.. but you have a burner that is entering safety lockout. There's always the possibility that it's a serious situation.

If the oil filter is partially plugged, the the partial vacuum in the tiger loop will eventually balance out with oil seeping thru the blocked oil filter over time as @EBEBRATT-Ed said. Once you reset it, the clock starts ticking, how long will it take to use up the oil on the fuel pump side of the filter. 3 minutes? 4 minutes? 8 minutes? I will wager just long enough for the temperature gauge to reach about 160°

As the oil filter becomes more clogged, that time will become shorter and shorter. At some point, the technician will need to arrive and find that oil filter completely covered with mud, sludge and other tank bottom deposits.

OR

You could try replacing the fuel filter.

After that, the rest of the blockage problem if any, are for the professionals.

An inline filter should be okay after only a year, but ya never know what might have gotten stirred up and put thru the line. A big flake of rust or some muck might be at your tank exit port too, causing a restriction.
I didnt mean to imply that you should change the cad cell, just that it's sometimes an easy thing to test without specialty tools or training if the primary includes a self test function (but you can also test cad cells with an ohmmeter). But, easy enough to change out if you wanted to try that.