[SOLVED] Impossible to assign a resource to an activity

We use PROJEQTOR since 4 years to plan a different project like mechanical, electrical project

In this new version (V5.1.4), when I click to the "+" to add a new assign in an activity, I cant choose a resource.
I have the same problem when I would like to change a hold assign in a hold activity (I cant change or add a new assign).

Can you help me to resolve this problem ?
For information, we haven't this problem in the last version.

thank you to your fast answer,

I already cleaned my browser cache (CTRL F5) and I have the same problem but it's not just me, it's all my time and we use different browser and not on the same localisation.

The last good version is V4.5.6 and now me a use internet explorer or Google Chrome (same problem for each browser)
Excuse me but I don't understand
"Also check for errors in log file" ?
How I can check the log file on my browser ?

Hi, you can find on the picture (i think) the different error when i try to add a resource.