I opened my Volla Phone today which is on Ubuntu 16.04 (OTA-14) and tried to update the phone and keep getting the following error:

Update failed

SignatureError:
sig path : 39d1b070083b5d7d304e8b4bcf6f7b92/android/cache/recovery/ubports-e5d8eb2f6599c4d03394f04c8b726a3d131bf4550a7a66a1236c08a2ebb8d1b1.tar.xz.asc
data path: 64bb5a99b35b13666273af26d9294226/android/cache/recovery/ubports-e5d8eb2f6599c4d03394f04c8b726a3d131bf4550a7a66a1236c08a2ebb8d1b1.tar.xz
keyrings: ['b3e0e991823eece4db1b1c50319a846f']['var/lib/system-image/keyrings/image-signing.tar.xz']
blacklist: 8e99110311bd347dda46e16c3a3f9951 /var/lib/system-image/blacklist.tar.xz

I also tried using the UBports Installer following the instructions https://volla.online/en/resources/manuals/How-to-flash-Volla-OS-on-Volla-Phone.pdf to reinstall Ubuntu Touch, but it gets stuck during the flashing phase.

Any idea what my issue is? Is there any other methods for updating Ubuntu Touch? Thanks in advance.

Wanted to provide an update.

I didn't have a USB drive large enough to have both Ubuntu and the Installer installed. So I had to find my old PC. I finally got Ubuntu installed. That fixed the issue, I'm updated to OTA-21 now!

Thanks for the help @Lakotaubp