Links sent by Email on FrappeCloud are incorrect

I’m not sure if this is a FrappeCloud issue or a Frappe issue, but here it goes:

I have few sites on frappe cloud, all running frappe and erpnext. When the system is sending out an email, the link it generates goes to an subdomain that is incorrect.

Example:
http://url326.example.com/ls/click?upn=ngTzunvWNoiEz704lA9oJzRm3-2B7JJRBXFfKT-2FU8ADdqgc2ZuCau-2FoYiKyWRs-2BbwRLGuMCdw6AU98XGky7ZA-2Bhw-3D-3DZ0i0_ldBqoRp1Z8qChbMWP0MSRANFYbFBG47Nbk5yLBC4flezoxILRnwegyQ1QOAi1JWNFmA2XHALiafcHIsY5ovj0rKDzG22qExBjxMNPqn1orAiHvMq-2FZrvWTr1QaxAiauNPRxGckxpV4zHgLRGqWjiqxBH2jlFl-2Bg8xNtk71YouuWXKvQOk0aw06mmnE8ghTHOC7fyTQ4iq2uAp4c0awpA6A-3D-3D

In this link, the subdomain, url326 is incorrect and it shows up in every email sent by my frappe installation. The domain itself is correct. How can I fix this?