read here; but if this doesnt solve your problem, it could be from other things ( for me is working all the time, last night it do 15 sites ) you could delete isk related stuffs.
03/18/2019 09:35:55: Review: MARBEL-1v3 XXXXXXXXXXXXX Sites : 15; Total: 1875884419 ISK # Session: 278293505 ISK ; 494 killedrats . .
03/18/2019 11:50:22: Review: MARBEL-1v3 XXXXXXXXXXXXXXX Sites : 15; Total: 1909254860 ISK # Session: 311663946 ISK ; 536 killedrats .