Sluggish acceleration after rebuilding the transmission

i recently rebuilt the automatic transmission. I am just a novice but i believe i did everything correctly. installed transmission and it was very sluggish at take off. also the cog transmission light came on the instrument panel. i heard that it went into a safety limp mode and the computer needed to be reset. i purchased an inexpensive scanner tool but when i tried it on the transmission said unable to communicate. it did however seem to communicate to the engine. i called a transmission guy who i know he confirmed it needed to be reset. i brought it to him his computer was also unable to communicate with it. i wiggled wires by computer nothing. checked fuses, wires that were connected to transmission. checked transmission fluid level. I am pretty sure it is something connected to me working on the transmission.