Facebook Marketing - cant add ad account to Shopify

[Fadie]

Hi,

I am trying to add my personal account to my Facebook Marketing page on Shopify. 

My account appears with a 'connect' button however when I press connect it says I need to add the account to by Business Manager. When i try do that i get an error message with no details on the error.

Any ideas how to fix this?

[Ferdous86]

This ad account couldn’t be added to the selected Business Manager because you’ve reached the maximum number of allowed ad accounts. Contact Facebook support to learn more ?