Optus accidentally blocked all its users from accessing websites through the bit.ly URL shortener whilst trying to block a phishing email on Monday morning.
The block restricted access to any bit.ly link, which are popularly used on social media platforms like Twitter to shorten web page links to just a few characters.
Optus users instead were directed to an error message page informing them that the website had been blocked "for your protection".
The telco revealed to iTnews that it had made the error whilst attempting to block a link to a phishing email targeting Optus customers that it discovered on the weekend.
While it has lifted the bit.ly block, Optus warned it could take up to 48 hours in some cases for users to regain access.
"Optus sincerely apologises to all customers that were affected by this error," a spokesperson said.
Just a few of those affected included news sites like the Financial Review, Daily Telegraph, ABC, and news.com.au, as well as resources such as Google Maps.
Bit.ly claims its platform is used by "millions" of global customers who have created "billions" of shortened URLs.