I followed the instructions in the link in the previous answer from Sania, I am still doing the tests (the problem is probably due to an extension I guess), Worfence and Jetpack are OK. I don’t have a solution to my problem yet but I’m logged, and I think I will find it in the next hour so thank you both!
THANK YOU! (I was hoping I wouldn’t need to put my hands in the engine…) Best regards 🙂
