Extension for client in Texas. (rejected)

[Jack from Ohio]

I know that the filing date and payment date for clients that live in Texas, is June 15, 2021.

Client in Texas requested an extension on June 2, 2021.  I processed the extension on June 2, 2021, and it was rejected.  Here is the rejection.

Federal Extension

"Form 4868can only be filed after the 'TaxPeriodEndDate' in the IRS Submission Manifest and on or before the due date to which the extension applies, unless Line 8 checkbox or Line 9 checkbox is checked."

Does the Texas due date extension, allow Form 4868 to be filed up until June 15, 2021?

I have searched far and wide.  There are many sources talking about what is allowed to be filed, but not a word about filing an extension.

Any help would be appreciated.

[Lion EA]

The IRS is not accepting e-filed extensions after 17 May, but you can paper file extensions for TX and the other states with later extension dates. (Check with your software for the latest information.) 

https://www.irs.gov/forms-pubs/extension-of-time-to-file-your-tax-return

"Victims in FEMA Disaster Areas: Mail Your Request for an Extension of Time to File

To request an extension to file your federal taxes after May 17, 2021, print and mail Form 4868, Application for Automatic Extension of Time To File U.S. Individual Income Tax Return.  We can’t process extension requests filed electronically after May 17, 2021.

Find out where to mail your form."