Environment variable validation error

# service: rxd-administration

frameworkVersion: "2.35.0"
useDotenv: true
unresolvedVariablesNotificationMode: error
configValidationMode: error

plugins:
  - serverless-offline
  - serverless-plugin-git-variables
  - serverless-dotenv-plugin
  - serverless-domain-manager

custom:
  domains:
    local: local-api.carierx.app
    develop: develop-api.carierx.app
    staging: staging-api.carierx.app
    prod: api.carierx.app
  stageVariables:
    gitBranch: ${opt:stage, git:branch}
  customDomain:
    domainName: ${self:custom.domains.${self:provider.stage}}
    basePath: "administration"
    stage: ${self:provider.stage}
    createRoute53Record: true

package:
  excludeDevDependencies: true
  exclude:
    - /node_modules/** # no need to add this yourself, this plugin does it for you

provider:
  stage: ${opt:stage, git:branch}
  name: aws
  runtime: nodejs12.x
  region: ${env:AWS_REGION_CRED, 'us-east-1'}
  versionFunctions: false
  tags:
    project: rxd-administration
  lambdaHashingVersion: 20201221

functions:
  - ${file(./tenant/serverless.yml)}
  - ${file(./auth/serverless.yml)}

resources:
  Outputs:
    AuthorizeUserLambdaFuncExport:
      Value:
        # Ref: SharedLambdaLayer
        Ref: AuthorizeUserLambdaFunction
      Export:
        Name: AuthorizeUserLambdaFunction

Serverless: Running "serverless" installed locally (in service node_modules)
Serverless: DOTENV: Loading environment variables from .env.local, .env.local:
Serverless:      - STAGE
Serverless:      - SLA_DROPOFF_AFTER_MINS
Serverless:      - AWS_ACCOUNT_CRED
Serverless:      - AWS_ACCESS_KEY_ID_CRED
Serverless:      - AWS_SECRET_ACCESS_KEY_CRED
Serverless:      - AWS_REGION_CRED
Serverless:      - LOGLEVEL
Serverless:      - LYFT_REFRESH_TOKEN
Serverless:      - LYFT_ACCESS_TOKEN
Serverless:      - LYFT_CLIENT_ID
Serverless:      - LYFT_CLIENT_SECRET
Serverless:      - LYFT_WEBHOOK_VERIFICATION_KEY
Serverless:      - SMS_APPLICATION_ID
Serverless:      - SMS_REGISTERED_KEY_WORD
Serverless:      - CLIENT_APP_URL
Serverless:      - SECRET_NAME_FOR_LYFT_REFRESH_TOKEN
Serverless:      - SECRET_NAME_FOR_LYFT_ACCESS_TOKEN
Serverless:      - LYFT_ACCESS_TOKEN_ROTATION
Serverless:      - AWS_XRAY_CONTEXT_MISSING
Serverless:      - _X_AMZN_TRACE_ID
Serverless:      - PHARMACY_LOGO_URL
Serverless: Deprecation warning: CLI options definitions were upgraded with "type" property (which could be one of "string", "boolean", "multiple"). Below listed plugins do not predefine type for introduced options:
             - ServerlessOffline for "apiKey", "corsAllowHeaders", "corsAllowOrigin", "corsDisallowCredentials", "corsExposedHeaders", "disableCookieValidation", "enforceSecureCookies", "hideStackTraces", "host", "httpPort", "httpsProtocol", "lambdaPort", "noPrependStageInUrl", "noAuth", "ignoreJWTSignature", "noTimeout", "prefix", "printOutput", "resourceRoutes", "useChildProcesses", "useWorkerThreads", "websocketPort", "webSocketHardTimeout", "webSocketIdleTimeout", "useDocker", "layersDir", "dockerReadOnly", "functionCleanupIdleTimeSeconds", "allowCache", "dockerHost", "dockerHostServicePath", "dockerNetwork"
            Please report this issue in plugin issue tracker.
            Starting with next major release, this will be communicated with a thrown error.
            More Info: https://www.serverless.com/framework/docs/deprecations/#CLI_OPTIONS_SCHEMA
Serverless: Deprecation warning: Support for "package.include" and "package.exclude" will be removed with next major release. Please use "package.patterns" instead            More Info: https://www.serverless.com/framework/docs/deprecations/#NEW_PACKAGE_PATTERNS
Serverless: Packaging service...
Serverless: Excluding development dependencies...
Serverless: Uploading CloudFormation file to S3...
Serverless: Uploading artifacts...
Serverless: Uploading service rxd-administration.zip file to S3 (127.64 KB)...
Serverless: Validating template...
Serverless: Updating Stack...
Serverless: Checking Stack update progress...
..............................
Serverless: Operation failed!
Serverless: View the full error output: https://us-east-1.console.aws.amazon.com/cloudformation/home?region=us-east-1#/stack/detail?stackId=arn%3Aaws%3Acloudformation%3Aus-east-1%3A212556752574%3Astack%2Frxd-administration-local%2F51d7b540-9dd8-11eb-a5b7-0e706f74ed45

 Serverless Error ----------------------------------------

  An error occurred: AuthenticateUserLambdaFunction - Resource handler returned message: "1 validation error detected: Value at 'environment.variables' failed to satisfy constraint: Map 
keys must satisfy constraint: [Member must satisfy regular expression pattern: [a-zA-Z]([a-zA-Z0-9_])+] (Service: Lambda, Status Code: 400, Request ID: 91e93afc-3abc-49c7-b38b-c0ef7832022e, Extended Request ID: null)" (RequestToken: e0b9e74e-629f-1ce8-f0a9-f718e67fb974, HandlerErrorCode: InvalidRequest).

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  Your Environment Information ---------------------------
     Operating System:          win32
     Node Version:              12.19.0
     Framework Version:         2.35.0 (local)
     Plugin Version:            4.6.0
     SDK Version:               4.2.2
     Components Version:        3.9.2