In letters received this week, John Dehlin and Kate Kelly were told to appear at hearings before their local Church of Jesus Christ of Latter-day Saints (LDS) leaders for alleged acts of "apostasy." Such hearings are known as church court.
Dehlin, who lives in Logan, Utah, is the founder of several long-running, Mormon-themed websites, blogs and podcasts, including Mormon Stories and Mormon Matters.
The online forums are for Latter-day Saints who have struggled with doubt or questioned church teachings on issues including polygamy, race relations, church history, and the status of LGBT members.
After Dehlin wrote online that he no longer believed many of the "fundamental" LDS church claims, he was told to resign by June 18 or face a church court.
"I am greatly concerned about the impact these and other statements and actions are having," said the letter, from a church leader Dehlin said he had never met.
On Wednesday he said he would not resign.