EXCLUSIVE

Hannah B -- a front-runner to be the next 'Bachelorette' -- got a rude homecoming when her sorority denied producers a chance to shoot promos with Hannah at her alma mater.

Sources close to the situation tell TMZ ... 'Bachelorette' producers reached out to the University of Alabama's Alpha Chi Omega chapter about shooting interior and exterior shots at the sorority house where Hannah Brown partied before graduating in 2017.

Quick SPOILER ALERT.

Hannah, who placed 7th on the current 'Bachelor' season with Colton Underwood -- is rumored to be the new 'Bachelorette' ... and the fact she's shooting promos is a big hint the rumors are true. However, there's been no official announcement.

Our sources say ΑΧΩ turned down Hannah due to security concerns. We're told there are hundreds of members on campus, and sorority officials felt the show could bring unwanted publicity and attention.

Hannah -- who, BTW, graduated magna cum laude -- was still able to shoot promos in other campus locations Friday ... including the Crimson Tide's Bryant-Denny Stadium.

Worth noting ... just because Hannah's shooting promos doesn't mean she's a lock to hand out roses. Remember what happened to Caila Quinn? She recorded promos, too, in 2016, but producers ultimately went with Jojo Fletcher.