Ok oil temp light

[subarulemon?]

I recently purchased a 1999 Forester with 124,000 miles on it. l picked it up from the seller and drove 20 miles to my guy, it ran fine. My guy changed oil and filter, also had the fuel filter and air filters replaced. When l started it up the service engine soon light came on along with the "ok oil temp" light, which was flashing. Changed the MAF sensor and still the same issues. Any feedback would be appreciated, thank you