INDIANAPOLIS (AP) — A spam filter blocked as many as 70,000 emails sent to Indiana legislators about a contentious bill that aimed to place restrictions on teaching about racism and political topics.

The Indiana State Teachers Association said it found out less than a week before the legislative session ended early Wednesday about emails sent through a form on its website not reaching the accounts of lawmakers, The Indianapolis Star reported.

ISTA executive director Dan Holub said the teachers union believes the messages had been blocked since January and possibly fewer than half of the nearly 120,000 emails sent through its website were delivered.

The head of the agency that handles technology services for the General Assembly said it has had a policy since 2012 limiting how many emails can come from a single source. Legislative Services Agency executive director George Angelone said that was in order to protect against email spam attacks.

Holub said the teachers union has been using the same company to provide form emails for several years without encountering messages being blocked.

The Senate Republican caucus suggested that members of the public who want to contact their lawmaker do so by sending an email from their personal account or make a phone call.

The teachers union was opposing a bill endorsed by House Republicans that included a prohibition on teaching that anyone should feel “discomfort” or “guilt” about their race, gender, religion or political affiliation. The bill failed when it did not advance through the Senate.