i solved the issue by adding an exception for wifi in battery saving management. MY Phone is in french so i'm not sure of the correct menu translation but here's what i did : Go to the settings menu > battery > advanced settings. On the applications list, select wifi. Select power saving functions. Go to the system tab and select wifi. If you don't have access to the apps list in the battery menu, You can find It this way : Settings > applications. Display all remaining applications. On the top right corner, click on the three dots and select display system procès, find wifi and click on It. Click on advanced options, then battery, then power saving functions. Go to the system tab and select wifi. And it's done It worked for me ! Hope it'll help !
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