Please see the steps below for clearing the hidden HTML text:
1. Open the Letter Template in the Editor and copy the Letter Text
.png?Policy=eyJTdGF0ZW1lbnQiOlt7IlJlc291cmNlIjoiaHR0cHM6Ly9kemY4dnF2MjRlcWhnLmNsb3VkZnJvbnQubmV0L3VzZXJmaWxlcy8xMTEyOC8xNDIwNS9ja2ZpbmRlci9pbWFnZXMvMSgxMTcpLnBuZyIsIkNvbmRpdGlvbiI6eyJEYXRlTGVzc1RoYW4iOnsiQVdTOkVwb2NoVGltZSI6MTc4MDUxOTg3MX19fV19&Signature=ntTizw2jIaJdGANXJpeMwI7ga86~i5iET0nhGduaeqfaEwLpEufbI7VC5pYA6Pa0Ht3-cw9TVImkosCX5RjRywVC-pU3GFAHcaTbYQkWPrSp5WYam0l-K0IaCi5rllgGYFLnM8HjOQf25ZHHf5PcZQ1OSuKj5PKFa8htqpt3RCG6SLW2MHNy~0~9KblZTljgnrv0QoHyZfbcfqD5pecXHl8atJN-aQsEC0XKi~cZJT~ozP8vy334bHlY-Ju2RUXW-phkbb9s2CUJrUbSFJ4sqr9sNkZE2K~C5puJObzksKE7h7Hxwgyxc6Ck-HN34Hg1cQxTCtRTIVDArF6xBJyzyA__&Key-Pair-Id=K2TK3EG287XSFC)
2. On your web browser go to https://html-online.com/
3. Paste the letter text into the left side HTML, then click on Clean
.png?Policy=eyJTdGF0ZW1lbnQiOlt7IlJlc291cmNlIjoiaHR0cHM6Ly9kemY4dnF2MjRlcWhnLmNsb3VkZnJvbnQubmV0L3VzZXJmaWxlcy8xMTEyOC8xNDIwNS9ja2ZpbmRlci9pbWFnZXMvMig2MikucG5nIiwiQ29uZGl0aW9uIjp7IkRhdGVMZXNzVGhhbiI6eyJBV1M6RXBvY2hUaW1lIjoxNzgwNTE5ODcxfX19XX0_&Signature=noZ5vDwVuYG402N9FwvSwBmx3mqRmbeuZNdsIe~gh6C~EhtbnAREXfcjh23sJC3H2a~8NHHxlurN3Vz4NvBoO0EwDcjA-5wHuyTXoUOEXoDDxtyzQfTy~wR9~BHmUPzSz0US1ZjDs30NhSPxG7fsaTButFtf9zop1vmlcYw5F7NGj2gkQge54mFxSfsaOfPy3ZLHxBFlHe4gnyqoF8yLrkrKXLjqHosnerB8ZEpuof3s1rwABz7O3TvlsU2U4yH6xeUnFM9eD59mRLjhZGph21QhGfKKFgZyhycZrnBtCsT-~H2nRNF7woRJPkn9AsU8LQRwe4ti5FGX1tqrLwzhFQ__&Key-Pair-Id=K2TK3EG287XSFC)
4. Copy the HTML from the right side after the HTML has been cleaned
.png?Policy=eyJTdGF0ZW1lbnQiOlt7IlJlc291cmNlIjoiaHR0cHM6Ly9kemY4dnF2MjRlcWhnLmNsb3VkZnJvbnQubmV0L3VzZXJmaWxlcy8xMTEyOC8xNDIwNS9ja2ZpbmRlci9pbWFnZXMvMygzMykucG5nIiwiQ29uZGl0aW9uIjp7IkRhdGVMZXNzVGhhbiI6eyJBV1M6RXBvY2hUaW1lIjoxNzgwNTE5ODcxfX19XX0_&Signature=nuFADIMuUqplMmVJA9wlTtdvgxWrJPmGNfzTayoJsiayub1ssaGIns-1R3-xT-BdQX7jhlb3nG4cfoazAh~g-nd5uCJ3sIioNgx1VwDw8WuzKtmG7-bb1MYMDphrR~Jf~z4A2lR~heJreusEvnHFv0nMlYIfLddetViGVkp4AvLx9ClRbMcYMf1QJywAtyGC3Ah~aiVKeX4E8sAz7H5C1-AR8YgPv40gH6JPtrL3iW3Cq1XuMYSx5EsDrCM3-VkfdYX1dVsy9HecpTNj64bEvPm0w9Hj39uq1-yqCD9W2wdvWKGarL4p~4csa9THFCrFSvGvuKI21bO1LK0p7xjIMg__&Key-Pair-Id=K2TK3EG287XSFC)
5. Paste the HTML Text into the HTML Source Editor in Agentbox as per the steps below. Click update once added and then preview.
.png?Policy=eyJTdGF0ZW1lbnQiOlt7IlJlc291cmNlIjoiaHR0cHM6Ly9kemY4dnF2MjRlcWhnLmNsb3VkZnJvbnQubmV0L3VzZXJmaWxlcy8xMTEyOC8xNDIwNS9ja2ZpbmRlci9pbWFnZXMvNCgxMSkucG5nIiwiQ29uZGl0aW9uIjp7IkRhdGVMZXNzVGhhbiI6eyJBV1M6RXBvY2hUaW1lIjoxNzgwNTE5ODcxfX19XX0_&Signature=ruOJ~sto1cRZUz3lrzSBMOEUY63g7R5Rg-8qzbUFUZROiH7PwcZbfk7t3JQTj1E0BO7apLtbZBeoLOYGtDetoUdnaxZJg~uR0MvboRfwnUI7X3eWfcBgvEowGFkeM8wdxkGTMZoM7CUziEUGBFOD6-TM-KhCFyp0W5oDnf2a63F0DTa0ybfhxjBcg24hdKolRkxSuqf3ie9hikqrjWDq1K7sRzwKYDPYcBNcPbbOPwDfocfhuDlX6G7QREUpvU0qQrTYOUC6aozNtF0KZjNR9oH5m-nuVMcSFyFpu2UHA5DbNHDK135a2HZUG3qIZ-L6lr2ndppF2RM~q~~bTKfGpQ__&Key-Pair-Id=K2TK3EG287XSFC)