Can't change item email - keep receiving Internal server error

Hello,

I try to use API v2 console with this request:

mutation {
change_column_value (
board_id: 493115024,
item_id: 496948433,
column_id: “email”,
value: “{\“email\”:\“a.b@gmail.com\”,\“text\”:\“a.b@gmail.com\”}”) {
id
}
}

The board exists and item exists - I used this query before:

query {
items_by_column_values (board_id: 493115024, column_id: “email”, column_value: “o@a.com”) {
id
}
}
received response:

{
“data”: {
“items_by_column_values”: [
{
“id”: “496948433”
}
]
},
“account_id”: 5856938
}

So when I attempt to change the email value, I keep receiving internal server error 500.

I researched the forum and tried many things. But any complex value requiring {} substructure returns me the error 500.

What’s going on?