I'd look for a loose wire somewhere at or prior to these outlets. more than likely a neutral or ground. Could be at the main breaker panel or a junction box before as well as anything on the circuit such as swithches and light switches. Unscrew and Check the wire nuts. If you have the receptacles that the wire stabs into the back, these are notorious for bad connections and the NEC doesn't allow them anymore. If you have those then replace them with a receptacle with screw terminals or use the screw terminals on those. If you have a gfci outlet prior to these then it could be bad or have a bad connection.
Test everything with a voltage tester on the circuit and deenergize the circuit by tripping the breaker and retest everything before touching any wires. If all this is over your head, then hire an electrician.