Context Attributed strings do not translate

I downloaded this wp-invoice plugin and the string “E-mail Address:” has no context attribute.

My guess is your translation file does not reflect the strings used in the code of the plugin.

I don’t recommend adding strings manually.

Ensure your PO files are in sync with the actual strings that are translatable.

Relevant manual pages:
* Configuring your bundle
* Working with templates

Is it possible that a particular string isn’t translatable at all?

That’s always possible, but doesn’t seem to be the case for the “E-mail Address:” string.

My PO files should be in sync.

I downloaded your plugin and can clearly see that none of the source code uses message context. So either your PO files are NOT in sync, or you’re not running the same plugin I downloaded. Please clarify the exact version.

Version: 4.1.7

Good, we’re talking about the same plugin.

But I don’t see how the msgctxt was added.

It’s probably an old file. The wp-invoice plugin has probably been updated since your file was created and the author changed a load of the strings.

and those are the ones that don’t translate on the website

Exactly as I’ve been saying. Your PO file is not in sync with the plugin code. See the links I posted earlier today for how to update your translations when the plugin changes its strings.