Canadians can file their tax returns online again after the Canada Revenue Agency took the service down as a precautionary measure on Friday.
Services returned to normal late Sunday.
A notice was posted on the agency's website through the weekend that officials detected “an Internet vulnerability” and took down many of its services, including electronic tax filing.
The services affected included “My Account,” “My Business Account,” “Netfile,” “EFILE” and “Auto-Fill My Return.”
The CRA says the services were taken offline as a precaution and its website was not hacked.
A spokesman for the agency said in an email Sunday night that officials worked around the clock to address the vulnerability.
“We are now confident that the solution has been rigorously and successfully tested and services returned online,” Patrick Samson said.
The CRA was not the only government website offline over the weekend.
Statistics Canada's site was down during the weekend, but was put back online late Sunday.
The agency also cited an “internet vulnerability” but is confident its information and systems are now safe.