Input switch relais became slow on Easysolar 5000

[HolgerN]

After 5 years perfect running a Easysolar is no moore so fast in switching from 230V input to inverter mode. It is an off-grid system and 230V comes from a generator in winter time. This year I notice that the switch relais, which switches back to battery inverting after generator input, is no more so fast. Lights are flickerung and some electronic in the house resets. Is that just the relais itself and should be exchanged or is there any other reason?