[SOLVED] Long activity showing time with some users

Hello,
We recently encountered problems to show activities, only with a limited number of users (2 users).
For those users, it takes about 30 seconds to load activity, and for some activities, only the history is shown (this is more problematic). The users have access to these activities.
One of the two account is the admin account, so I created a new admin account in replacement, and all work perfectly with this new account.
The other account is an employee account, so we can't create a new one, as it is already affected on several projects.
I have attached the log file, but I don't see any error inside.

Any idea on what to do to solve this issue?

We don't customize any php file, but I tried to change the user parameter to disable History display, and now it seems to work!
The activity load time is back to normal values, and I have access to activities details that I have not before.
After verification, other users that don't have the problem have the history display disabled.

Maybe these activities have lots of history, that takes a long time to load...

Thanks for your help.

Yes, history archiving is well activated, but archiving period is set to 365 days, so maybe we will reduce that period.
Nevertheless, it's not a big deal, because we don't use histories very much.