import re
text = """ntpd process is not running on lnx31 contact: app-support. @monitoringautomation
ntpd process is not running on lnx31 contact: app-support, @monitoringautomation
ntpd process is not running on lnx31 contact app-support @monitoringautomation"""
print( re.findall(r"(?i)\bcontact:*\s*([^,.\s]+)", text) )