If . or /path/to/Script are not in your crontab's PATH variable, it cannot find the script. If the script is in /path/to/Script, change your crontab to either:
*/1 * * * * cd /Path/To/Script && ./Script.sh
Or
*/1 * * * * /Path/To/Script/Script.sh
Also, "*/1" means every 1 minute and "*" means every minute, so the "/1" is unnecessary