Can I still e-file 2016 returns in ProSeries (2/20/2021)?

[ejvtaxpro]

Client's CA 2016 return never received (he was not my client until 2019); I prepared 2016 CA return after getting IRS 2016 transcript, just tried to e-file it and am getting no feedback -- the "green thumbs up" or "red thumbs down" are only showing 2018 and 2019 activity, and this client continues to sit in "Pending" tab, says it's ready to e-file. Can I still e-file CA 2016? 

Thanks! 

[Just-Lisa-Now-]

Current year and 2 years prior, 2016 and 2017 are out of the Efile game

[ejvtaxpro]

Thank you!!