I have gained access to client's GTM = GTM-5MPXZH6
But, I am NOT seeing that GTM on their website. It needs to be installed.
whitney.zelig@gmail.com you need to let them know or their developer that it is not on the site. It has not been published and there are NO CONTAINERS. 

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Thanks Hector  I will give this to them to pass on to their developer!

sent. check back in a few days to see if they did it

No problem and thank you for following up. 
I also CCD Tiffany on the email you sent me. I provided the 2 Google analytics accounts for her in that conversation. 
I will check in a few to see if they have installed it. 

I have already verified that the GTM is installed on site. 
I have also installed Optinmonster script, container and published them. 
Fixed error and sent invites to other team members.