Usually that's due to a cord issue. Even in the worst of conditions Odin3 will detect the device regardless of which version of Odin3 your using. For the J7 I would suggest Odin3.13.3. You must first return to device back to official status. You may need what's called a combination or repair file. Go to https://samsungfirmware.net/category/samsung-repair-full-4-files-firmware/ and enter your devices model number, then scroll down to find the (binary) firmware. Install via Odin3. Good luck.
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Usually that's due to a bad cord issue. Make sure you have the latest Samsung driver installed on your PC. Even in the worst of conditions Odin3 will detect the device regardless of which version of Odin3 your using. For the J7 I would suggest Odin3.13.3. You must first return to device back to official status. You may need what's called a combination or repair file. Go to https://samsungfirmware.net/category/samsung-repair-full-4-files-firmware/ and enter your devices model number, then scroll down to find the (binary) firmware. Install via Odin3. Good luck.
Usually that's due to a cord issue. Even in the worst of conditions Odin3 will detect the device regardless of which version of Odin3 your using. For the J7 I would suggest Odin3.13.3. You must first return to device back to official status. You may need what's called a combination or repair file. Go to https://samsungfirmware.net/category/samsung-repair-full-4-files-firmware/ and enter your devices model number, then scroll down to find the (binary) firmware. Install via Odin3. Good luck.