State what work occurred and when the last normal use was. The timing can direct the assessment towards the installation as well as the appliance.
What the observation means
Do not assume the oven itself failed just because its display is now blank. Equally, restored lighting elsewhere does not prove that the oven's supply and controls are correct. Concealed connections should not be opened by the owner.
A useful next step
Contact the person responsible for the electrical work and describe the oven's current display state. Keep the repair business informed if further appliance assessment is needed. Do not bridge an isolator, change a fuse rating or use an improvised extension supply.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.