Blank page or "invalid" when trying to author or administer

Blank page or "invalid" when trying to author or administer

Dear Zoho experts,

My customer is building a couple of sites with Zoho and has asked me to look at the SEO. He has made me author and administrator of his sites and I have received emails from Zoho with links to them. I have created a user-id on Zoho and can log into Zoho OK but when I click the links I either get a blank page or "INVALID".

I am new to Zoho. Can anyone advise?

Regards

Geoff