The potential advisor suddenly stopped answering my emails. What should I do now? Sorry for yet another 'professor does not respond my email' question. I searched through other similar questions, however their context was slightly different from mine.

I am a M.Sc. graduated from Asia looking for a PhD position abroad (i.e. Canada). 

About the 9th of December, I sent an email to a professor in one of the Canadian universities, asking to join his research group as PhD student. He initially found my CV and transcripts interesting and requested for some recommendations letters being sent to him.
It lasted until the 21th of December when all of my references finally sent their recommendation to the professor and then I notified him about it,  however I didn't receive any response from him.

Because of the new year holidays, I found the delay normal and I waited until 7th of January (a week ago) and still no response! Then, I sent another email to him, politely asked about the status of my application and recommendations which have been sent to him and he has not answered this email too.

The professor was really positive in our initial contact, so I don't know if I should consider this type of ignorance as a rejection and move on or I need to make other decisions. Actually, I am also interested in research of one of his colleagues and If I knew his final decision about my application I could start talking to the other faculties before the deadline pass.

P.S: In this university, the admission decision is completely based on finding an advisor willing to support your research through your graduate study.



Update: I sent another reminder email to him after a couple of weeks, politely requested for a feedback if he received my email. I used email tracker software and I found he opened my email and still no answer.
At some universities, there is a quiet period between the application submission deadline and the first round of interviews, during which faculty and applicant communication is discouraged. 

As faculty, I've found such quiet periods annoying but understand the rationale which is to level the playing field by suppressing off-channel communications with a secondary purpose of limiting too much badgering on the part of applicants. 

Or the professor could be skiing or preparing for the new semester. Either way, I'd hesitate to badger too much. 

update: If I found a prospective student used an email tracking program on me, I'd drop them from consideration immediately. See: Is it rude to use tracking softwares for the emails that you send to potential advisors?