Why am I received the error 'This account has been locked because our systems have detected unusual traffic from your computer network'?

This issue is occurring because you are logging in too frequently, you are therefore hitting the below described limits:

Login Request Limits

Successful login requests are restricted to 100 request per minute.. In the event of a breach of the login limit the account will be prevented from creating new login session for a 20 minute period. The error TEMPORARY_BAN_TOO_MANY_REQUESTS will be returned in these circumstances. All existing sessions will continue to be valid.

Please follow the Best Practice advice detailed via https://docs.developer.betfair.com/display/1smk3cen4v3lu3yomq5qye0ni/Best+Practice#BestPractice-SessionManagement relating to session management to prevent this problem from occurring.