iPhone SE adding Gmail account return 500 error

I have an iphone SE first generation (2017) with last version of OS (15.8.3). I had to delete one of my email accounts because of some problems on the iphone. When i want to add it again, i can add my email , then i have to authenticate and google returns me a 500 error each time. Another person in France has this issue with an iPhone 8. I tried to - Clear browser cache and cookies (chrome version on iphone) - Disable double authentification in Google security account - Reinstall iphone and restore I still have a 500 error at authentification ... I know that 500 error is server side but it seems to come from malformated datas send througth authentification. How can I deal with this?