The No Vote to BJP group had been disabled “in error”, Facebook said on Friday and restored it.

“The group was temporarily blocked in error but has since been restored,” a Facebook spokesperson told The Telegraph in response to a question.

Sources in the company said an investigation was under way to find out what kind of error, “algorithmic or otherwise”, had led to the axe on the group.

Members of the group welcomed the restoration. “Because of a collective fight, the No Vote to BJP group is back. Greetings to all those who stood behind us. The fight against the BJP will continue,” said the group’s first post after the restoration.

The disabling of the group had triggered protests on social media.

The group members had said the disablement happened around Wednesday-Thursday midnight, with the administrators receiving a notification that alleged the group had not followed Facebook’s “community standards”.

The group was restored around 2.45pm on Friday, the administrators said. “This group’s activity was reviewed by Facebook and the group was restored,” read a notification on the group’s activity log.

“The group was disabled with a vague note about not following Facebook’s community standards. But we were not informed how (the group had violated these standards),” said Sabyasachi Mukherjee, one of the group administrators.

“Even when the group was restored, there was no update on the specifics of the (purported) violation. This is exasperating.”

Mukherjee said: “Freedom of speech and expression is the bulwark of any democratic space; whether real or virtual. We wish Facebook keeps this in mind.”

The group, which had rallied people against the BJP in the run-up to the Bengal Assembly polls and was credited with a key role in the party’s crushing defeat, counts over 33,000 members.

Just before receiving the notification of disablement, group administrators had received notifications about the deletion of several of the group’s posts on the ground of violation of community standards. Most of the notifications are now gone and the posts are back, the administrators said.