Unable to sign up In Jira service management portal. ReCAPTCHA asking repeatedly.

[Venkat Jira Admin]

Hi,

We are using Jira Cloud premium. For adding new customers to Jira Service Management portal, admin has sent the invitation. New users try to sign up on to the JSM portal. It is asking reCAPTCHA Again and again, and it's showing "we had like to make sure it's really you creating your account. Please confirm you are not a robot" error. Please give the solution to this error.

Thanks in Advance.