both pam_sotp 0.3.1 and 0.3.0 have a bug that prevents the PAM module
(pam_sotp.so) from working when the option pw_lifespan is not specified
in the service configuration file.

There is an easy fix for this: add pw_lifespan=0 (or some other value
if you want to enable password lifespan) in the configuration file and
pam_sotp should work.

pam_sotp 0.3.2 fixes this bug


--
Pedro Diaz