All certificates issued in the last 90 days and validated with TLS-ALPN-01 challenge are affected. You need to (force) renew the certificate according to your ACME client’s directions.
Nil-Coalescing Operator "The nil-coalescing operator (a ?? b) unwraps an optional a if it contains a value, or returns a default value b if a is nil. The expression a is always of an optional type. The expression b must match the type that’s stored inside a."