Currency not working on checkout!!

Hello,

I used this plugin for a while, and suddently it stopped working.

The conversion works good, but when you go to the cart/checkout page it switches back to EUR (default)

• Multiple allowed is ON
• I tried to delete plugin and install again (data stays somewhere), not working
• Tried to delete plugin via FTP (data stays still somewhere)
• I disabled caching
• Used currency switcher on checkout, clicking on PLN, switched directly back to EUR
• On staging website it works, with same plugins.
• I tried other currency plugins they worked

I want to use this plugin, what is wrong en what can i do about it? I litterly tried everything and searched each topic/documentation.

Is it maybe possible to delete plugin data and install it from scratch again ?

My ideas are empty, help.

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