Fortgates 5.4.0 to FAZ 5.6 just stopped sending logs

[FortiLearner]

Hi,

Has anyone had issue where, logs were working to FAZ from FGT.

FAZ 5.6

FGT 5.4

Devices were showing green then next day it was red and since then cannot send logs to FAZ.

Using LAN interface of the firewall.

disabled enc-alg

anyone can help?

Regards,

Learner

[chall_FTNT]

Which patch of FGT?  And what is the model?