I found the final solution in an old post: https://forum.cloudron.io/topic/9053/app-stuck-in-restarting-after-upgrade-7-4-1/2
This seems to have fixed everything. Thank you for the help everyone!
# rm /home/yellowtent/platformdata/sftp/ssh/ssh_host_rsa_key # rm /home/yellowtent/platformdata/sftp/ssh/ssh_host_rsa_key.pub # systemctl restart box