For the last 4 to 6 week or so Landon has consistently been CRANKY from 6pm-8pm. During those times he wails no matter what we do

Sometimes things we try may work for 10 minutes and sometimes they won't. There is no reason I can find for him be so miserable although at times it seems like it's his teeth or his tummy. I am at a loss!
We have tried alone and in combination:
Singing
Rocking
Dancing
Playing
Walks
Taking him outside
Taking him into a dark quiet room
Baths
Massage
Toys
Cold or frozen wash cloths
Teething tablets
Music
Now we just leave the house between those times but we can't stay in one place for long or we end up with him wailing. Like last night we went to my moms and he did well between 6-7pm but he wasn't happy from 7-8pm there. If we went to my sister's or a friends and changed the scenery @7pm he may have calmed back down but I am getting so exhausted doing this! Not to mention the other kids have a routine before bed and don't have enough time if we don't get home until 8pm.
I know this too shall pass but until then any suggestions? This can't be colic right? He's to old for that I thought. I am at a loss!
Many thanks!