Set the platform to 64 bit in ARM template

As you have not shared any error details , So there is only solution As the MS DOC provided by @evgeny, you can use the below template and deploy it as well. for example:-

use32BitWorkerProcess : bool // If need to enable 64 , provide false as value

TEMPLATE :-

resource symbolicname 'Microsoft.Web/sites@2018-02-01' = {
  name: 'string'
  location: 'string'
  tags: {
    tagName1: 'tagValue1'
    tagName2: 'tagValue2'
  }
  kind: 'string'
  identity: {
    type: 'string'
    userAssignedIdentities: {}
  }
  properties: {
    clientAffinityEnabled: bool
    clientCertEnabled: bool
    clientCertExclusionPaths: 'string'
    cloningInfo: {
      appSettingsOverrides: {}
      cloneCustomHostNames: bool
      cloneSourceControl: bool
      configureLoadBalancing: bool
      correlationId: 'string'
      hostingEnvironment: 'string'
      overwrite: bool
      sourceWebAppId: 'string'
      sourceWebAppLocation: 'string'
      trafficManagerProfileId: 'string'
      trafficManagerProfileName: 'string'
    }
    containerSize: int
    dailyMemoryTimeQuota: int
    enabled: bool
    geoDistributions: [
      {
        location: 'string'
        numberOfWorkers: int
      }
    ]
    hostingEnvironmentProfile: {
      id: 'string'
    }
    hostNamesDisabled: bool
    hostNameSslStates: [
      {
        hostType: 'string'
        name: 'string'
        sslState: 'string'
        thumbprint: 'string'
        toUpdate: bool
        virtualIP: 'string'
      }
    ]
    httpsOnly: bool
    hyperV: bool
    isXenon: bool
    redundancyMode: 'string'
    reserved: bool
    scmSiteAlsoStopped: bool
    serverFarmId: 'string'
    siteConfig: {
      alwaysOn: bool
      apiDefinition: {
        url: 'string'
      }
      appCommandLine: 'string'
      appSettings: [
        {
          name: 'string'
          value: 'string'
        }
      ]
      autoHealEnabled: bool
      autoHealRules: {
        actions: {
          actionType: 'string'
          customAction: {
            exe: 'string'
            parameters: 'string'
          }
          minProcessExecutionTime: 'string'
        }
        triggers: {
          privateBytesInKB: int
          requests: {
            count: int
            timeInterval: 'string'
          }
          slowRequests: {
            count: int
            timeInterval: 'string'
            timeTaken: 'string'
          }
          statusCodes: [
            {
              count: int
              status: int
              subStatus: int
              timeInterval: 'string'
              win32Status: int
            }
          ]
        }
      }
      autoSwapSlotName: 'string'
      azureStorageAccounts: {}
      connectionStrings: [
        {
          connectionString: 'string'
          name: 'string'
          type: 'string'
        }
      ]
      cors: {
        allowedOrigins: [
          'string'
        ]
        supportCredentials: bool
      }
      defaultDocuments: [
        'string'
      ]
      detailedErrorLoggingEnabled: bool
      documentRoot: 'string'
      experiments: {
        rampUpRules: [
          {
            actionHostName: 'string'
            changeDecisionCallbackUrl: 'string'
            changeIntervalInMinutes: int
            changeStep: int
            maxReroutePercentage: int
            minReroutePercentage: int
            name: 'string'
            reroutePercentage: int
          }
        ]
      }
      ftpsState: 'string'
      handlerMappings: [
        {
          arguments: 'string'
          extension: 'string'
          scriptProcessor: 'string'
        }
      ]
      http20Enabled: bool
      httpLoggingEnabled: bool
      ipSecurityRestrictions: [
        {
          action: 'string'
          description: 'string'
          ipAddress: 'string'
          name: 'string'
          priority: int
          subnetMask: 'string'
          subnetTrafficTag: int
          tag: 'string'
          vnetSubnetResourceId: 'string'
          vnetTrafficTag: int
        }
      ]
      javaContainer: 'string'
      javaContainerVersion: 'string'
      javaVersion: 'string'
      limits: {
        maxDiskSizeInMb: int
        maxMemoryInMb: int
        maxPercentageCpu: int
      }
      linuxFxVersion: 'string'
      loadBalancing: 'string'
      localMySqlEnabled: bool
      logsDirectorySizeLimit: int
      managedPipelineMode: 'string'
      managedServiceIdentityId: int
      minTlsVersion: 'string'
      netFrameworkVersion: 'string'
      nodeVersion: 'string'
      numberOfWorkers: int
      phpVersion: 'string'
      publishingUsername: 'string'
      push: {
        kind: 'string'
        properties: {
          dynamicTagsJson: 'string'
          isPushEnabled: bool
          tagsRequiringAuth: 'string'
          tagWhitelistJson: 'string'
        }
      }
      pythonVersion: 'string'
      remoteDebuggingEnabled: bool
      remoteDebuggingVersion: 'string'
      requestTracingEnabled: bool
      requestTracingExpirationTime: 'string'
      reservedInstanceCount: int
      scmIpSecurityRestrictions: [
        {
          action: 'string'
          description: 'string'
          ipAddress: 'string'
          name: 'string'
          priority: int
          subnetMask: 'string'
          subnetTrafficTag: int
          tag: 'string'
          vnetSubnetResourceId: 'string'
          vnetTrafficTag: int
        }
      ]
      scmIpSecurityRestrictionsUseMain: bool
      scmType: 'string'
      tracingOptions: 'string'
      use32BitWorkerProcess: bool
      virtualApplications: [
        {
          physicalPath: 'string'
          preloadEnabled: bool
          virtualDirectories: [
            {
              physicalPath: 'string'
              virtualPath: 'string'
            }
          ]
          virtualPath: 'string'
        }
      ]
      vnetName: 'string'
      webSocketsEnabled: bool
      windowsFxVersion: 'string'
      xManagedServiceIdentityId: int
    }
  }
}