Attempting to opt out of the new EIC starting in July. Website is not allowing me to process. Is there another way to do this? I understand this month it will process.

[Critter-3]

If you cannot opt out on the IRS site and you do not want the payments then you can send the checks back  OR  just put the money aside and wait until you file your return to pay back the credit.  

https://www.irs.gov/credits-deductions/advance-child-tax-credit-payments-in-2021