Can't use bitbucket any more. Your connection is not secure

[Eddy]

I've been using Bitbucket for 2 years on my Macbook. Today I went to view one of my depots but I am getting the error message, Your connection is not secure. All other sites works, it's only Bitbucket.org that is giving me this error. I've tried using Safari and Firefox, neither work. I also can not connect using SourceTree. I am able to connect on my Windows computer so that rules out my router. I've deleted all expired certificates in Keychain and deleted cookies and cache. Does anyone know what the issue might be?

The Macbook's clock is set automatically and is displaying the correct time. In Firefox, when the website fails to load, I can see these 3 messages by clicking the Advance button,

bitbucket.org uses an invalid security certificate.

The certificate is only valid for search.dnsadvantage.com

Error code: SSL_ERROR_BAD_CERT_DOMAIN.

If I click on the last error, it opens another page which displays, https://bitbucket.org/ Unable to communicate securely with peer: requested domain name does not match the server's certificate. HTTP Strict Transport Security: true HTTP Public Key Pinning: false.

Is there somewhere else I need to go to locate more information about the error?

[Eddy · Accepted solution]

After some help from other forums, I scanned the Macbook using Malwarebytes but it found nothing.  However, when digging a bit deeper I followed the instructions here, https://support.malwarebytes.org/customer/portal/articles/2049286-?b_id=9511 and found 2 unknown DNS Server entries. Once I deleted them, Bitbucket worked again.  :)

[sydpao]

I am having the same problems, but this link is no longer active:

https://support.malwarebytes.org/customer/portal/articles/2049286-?b_id=9511