Thank you for so quick answer. Try to re-check Agt package and also extension but no luck. Have also deleted both Agt and extension and re-check/re-install but same pb. Have noticed that this issue occur only with Agt 4.5. FYI server is up and running v4.p3 and agt 4.5 since several years.
Also update ePO latest patch
Situation was too critical so It's what have done. Now all is OK. Server will be upgraded soon to 4.5 p3 . Again thank you for your help.