PHP Fatal Error

I have not been on the site using your plugin for quite a while and initially everything seemed OK, but after I visited the admin dashboard Tools > Currency Rates that is when things seemed to escalate; there was an error noted there (see below), and then when I went to the actual site (after the previous views being OK) it had a critical error message. At that point I checked the WP email to find the first error, and turned debug on in wp-config and reloaded.

1st error – An error of type E_ERROR was caused in line 76 of the file /home/awolonl1/bahter.sentlive.com/wp-content/plugins/artiss-currency-converter/includes/rates.php. Error message: Uncaught TypeError: reset(): Argument #1 ($array) must be of type array, string given in /home/awolonl1/bahter.sentlive.com/wp-content/plugins/artiss-currency-converter/includes/rates.php:76

2nd error -PHP Fatal error: Uncaught TypeError: Cannot access offset of type string on string in /home/awolonl1/bahter.sentlive.com/wp-content/plugins/artiss-currency-converter/includes/convert-currency.php:120

I checked the Github and someone else reported a similar issue last year, but as the plugin has been updated since I assume it is not the same. I will continue investigating to see if it is a plugin conflict or some code I have written in the past that is at fault, and will report back here if I find anything.