Translate plugin via language pack

You can have a look at https://www.shamimsplugins.com/docs/front-end-pm-pro/getting-started-2/translate/

Using Loco Translate Plugin
Dashboard > Loco Translate > Plugins > Front End PM PRO > Edit Template > Sync > Save
Dashboard > Loco Translate > Plugins > Front End PM PRO > {YOUR LANGUAGE} > Sync > Save
Now translate if there is any untranslated string.

Thank you for answer. The translation is complete, but I still only see English …

I tried to uninstall Front End PM + Loco Translate, clean the database and reinstall everything. I tried to translate (rename) the string in the default package (front-end-pm-en_US.po), but the change will not take effect on the page. I use the Astra template (child).

1. How you setup your language for the website? Does other plugins translation works?
2. For changing in default .po file, .po file is not used by wordpress to show translation. It is there so that we can make a translation and create .mo file. .mo file is used by wordpress to show translation.

The site is in Czech.

My procedure:

1.

2. Replacement of translation files –

3. https://paste.pics/2233bbfdbd9bf719a88fdb0032e37b73

4. Checking translations in a package – https://paste.pics/9c804079dcc10511ec0ae3a206cdac09 + synchronize.

PS: Translations of other plugins work properly.

The site is in Czech.

My procedure:

1. https://paste.pics/b3cb0f117f70bfa003d344b072a11e05

2. Replacement of translation files – https://paste.pics/77205fccb1bf77d731ccdbf220a3c510

3. https://paste.pics/2233bbfdbd9bf719a88fdb0032e37b73

4. Checking translations in a package – https://paste.pics/9c804079dcc10511ec0ae3a206cdac09 + synchronize.

PS: Translations of other plugins work properly.

I’ve already solved it. Translation files must be named cs_CZ ??