getting token expired error when accessing calendar events in SPFX webpart using GRaph API

I have created spfx webpart which displays calendar events using Graph API ..im getting "sp-webpart-workbench-assembly_en-us_f0d9d879eac858478672d13ba224a03e.js:19 Uncaught (in promise) Error: Error - Type : Token Renewal Failed - Description : Token renewal operation failed due to timeout - AADCorrelationId: " Error