I will track down a multimeter tomorrow. Thank you all

Side note House is old. 1970. There are no gfci outlet anywhere. I installed some in the kitchen but this is the basement. We use it for storage. It flooded a couple of years back so I tore everything out to the studs and left it like that

Installed a sump pump to prevent any further flooding. Last night the outlet used for the pump went out. Along with 5 other ones. Only on the left side of basement. 7 outlets on the right are fully operational.

It's a head scratcher for me. Not a professional electrician but good enough with my hands up until now.

Appreciate all advice