Having issues w/ Pro Sites & Clients upgrading theirs sites.

Hello,

I'm granting access in case you might need it. I'm using Pro Sites and some clients are having issues upgrading their sites. I'm getting this dialog.

"Your site was extended manually and may not renew automatically. If you have an active subscription this message will disappear once payment is received. Please contact us if you have any concerns."

Any idea if I"m doing something wrong?

Thank you for your help in advance,

Adrian