By the way, normally using pure functionals like OPBE is not a good idea, because this kind of functionals almost always severely underestimates excitation energies. Using PBE0 commonly is a much better choice.
You also forgot to add IOp(9/40=4) in keyword, in this case the excited state analysis by Multiwfn may be evidently inaccurate.
]]>What should I understand from these errors?
A similar calculation with a different DFT functional works without a problem. I can provide the .fchk and .log files for troubleshooting. Thanks