Respuesta :

1) Santa Anna had signed a treaty to grant Texas independence and Mexico refused to accept this treaty. 

2) Texas was bankrupt. 

3) Comanches and Indian groups threatened attack smaller Texan communities. 
Snowpaw
One reason is that mexico refused to accept the treaty santa anna had signed to give texas independence and second reason is that texas was technically bankrupt
( texas was unable to pay debt)
Hope this help