Domain help - showing the correct URL in browser

[Outer_Rim_Props]

Hello  Community 🙂 , I will be doing a search as well but I just can't seem to find the answer yet so posting here in hopes of getting this resolved.   I would like to change my domain name here on Shopify to a domain name I own on Squarespace , I cant transfer the domain over to Shopify yet , need to wait about 30 more days. 

So long story short , I registered and set up my e-commerce site here under thatsnomoonpropz.com , and I want to change it over to a domain name that I own over on  Squarespace  , we will called outertimprops.com . My LLC and everything is under outerrimprops /

Right now I point the outerrimprops on Squarespace  to thatsnomoonpropz which works , but the  thatsnomoonprops name pops up in the  browser not outerrimprops .  When I make outerrimprops my primary domain I get an error stating to many redirects. 

Not sure what I am doing wrong , just want my domain in the browser to show up correctly .. Do I need to wait to transfer my domain form Squarespace over before I can do this?  Hops this makes sense, making my head hurt 🙂