Time Machine backup fail

So mine gave me an error started last night after recent update. My disc drive is always connected and I have it on a weekly schedule as I don’t is it that much right now it has some error message of a apple file I’m not at the computer right now but can add the message when I get back to it I might restore to my last backup and see if that works then I’ll k ow for sure I have trouble shoot with no change

1 TB archive storage is too small for a 0.5 TB source device.

Roughly 2.5 to 3 times the input works well for providing some depth of backups, or a yet larger-capacity archive device for deeper backups.

An input of 0.5 TB best uses an archive device of between roughly 2 to 3 TB, or larger.

And getting a whole lot of Time Machine churn right around a macOS update is entirely normal and expected, and also right when you’re going to want that backup depth.

The EXACT text of the error message is essential in figuring this out.

I addition to the obvious issue of DESTINATION disk Full, Time Machine stages 'snapshots' -- lists of files to her backed up, on the boot drive, and if the boot drive is too full, those lists are purged to make space for other files and the backup cannot continue.

¿How full is the Source drive?