What to Do If an Error Occurs in Ondoku
Aug. 7, 2026
When using Ondoku, errors sometimes occur, and the text cannot be read aloud.
Errors may occur due to the network environment or the browser being used.
Even with the same text, it may be read normally if you try reading it again after a short wait.
However, once an error occurs, the text you want to read might fail repeatedly, resulting in multiple errors.
What are the causes of errors? Troubleshooting by error type
The causes of errors can be broadly divided into two categories:
- When there is a problem with the text to be read aloud
- When there is a problem with the usage environment
We will introduce the troubleshooting methods for each in detail.
1. When there is a problem with the text to be read aloud
Recommended character count
Ondoku has a recommended character count; exceeding this limit makes reading errors more likely to occur.
- Normal use: 5,000 characters
- When using SSML: 3,000 characters
These are the recommended character counts.
The text is the cause of the error
- It is not plain text (text without formatting)
- It is too long (above the recommended character count)
- It contains symbols
- The SSML is incorrect
These are major causes of reading errors. We will introduce troubleshooting methods for each.
Troubleshooting when the text is not plain text (unformatted text)
In Ondoku, text containing formatting cannot be read aloud.
Please make sure to use plain text for reading.
When pasting,
- Paste as plain text
select this option or use the following shortcut keys to paste.
- Win: Control + Shift + V
- Mac: Command + Shift + V
- Word
- PowerPoint
- Websites with formatting
Copying text from sources like these will include formatting.
If you paste text with formatting and try to read it, an error message saying "Some error has occurred in the entered text. Please try another text." will appear.
In the text box, it may look like plain text, but it remains text with formatting.
Troubleshooting when you want to read long texts
- Divide the long text into multiple parts, such as 2 or 3 parts
- Use the conversation feature to input text into multiple text boxes
Using these methods will make errors less likely to occur.
How to use Ondoku's conversation/dialogue feature. Make listening materials and long text creation more convenient with speech synthesis!
How to use Ondoku's conversation feature! Explaining how to use the conversation feature with images. Introducing specific examples of what the conversation feature can be used for.
Troubleshooting when reading text containing symbols
Ondoku is strictly a service that can read characters.
If unnecessary symbols are included, they may interfere with the reading or prevent it entirely.
Example: & < > : ; " = etc.
In particular, symbols used in SSML tags are likely to cause errors. Please remove as many symbols unrelated to the reading as possible.
If you want the symbols to be read aloud, please replace them with their names (e.g., in text).
Example: = Equals
2. Troubleshooting when there is a problem with the usage environment
Recommended internet speed for Ondoku
- Download: 5Mbps
If your speed is below the recommended internet speed, you may not be able to use the service comfortably.
You can check your current internet speed here.
External site: Internet Speed Test
Recommended browser for Ondoku
Ondoku recommends the latest version of Google Chrome as the browser.
The usage environment is the cause of the error
- Internet speed is slow
- JavaScript is disabled in the browser
- Not using a recommended browser
- A browser extension is interfering
- Some kind of blocking function is active
- There is some other cause in the usage environment
These are major causes of reading errors. We will introduce troubleshooting methods for each.
Troubleshooting when internet speed is slow
When internet speed is slow,
- Connect to a high-speed Wi-Fi or mobile network
for use.
Also, please try using tethering.
Troubleshooting when JavaScript is disabled in the browser
If JavaScript is disabled, reading cannot be performed.
Please enable JavaScript.
Check here for how to confirm if JavaScript is enabled in your browser.
External site: How to enable JavaScript
Troubleshooting when not using a recommended browser
Not using a recommended browser can cause various errors.
Please use a recommended browser.
Troubleshooting when errors occur even in a recommended browser
If you are experiencing errors,
- Switch the browser to Chrome
(However, if you are already using Chrome, try a different browser) - Try using Chrome's Incognito window
Please try these steps.
How to open an Incognito window
What is an Incognito window?
It allows browsing without saving website history or form input information.
It can disable cookies, cache, and extensions.
To use an Incognito window:
- Click "File" in the toolbar
- Select "New Incognito Window"
or
- Press [Ctrl] + [Shift] + [N] keys
to open it.
Please give it a try.
If it works in an Incognito window, it means that cookies, cache, or extensions are interfering.
- Delete cookies and cache
- Disable extensions
before trying Ondoku again.
Troubleshooting when some kind of blocking function is active
In the past, there was a case where "HTML became corrupted and reading was impossible when trying to use it on a workplace computer."
The cause in that case was a firewall installed in the workplace network environment.
We received a report that it became usable after having the IT department check it.
Please check if there are any blocking functions in the network environment you are using.
Try from another device (smartphone, tablet, or PC)
If a reading error occurs despite being in a recommended environment due to issues with the usage environment, changing the device may solve it.
Please try a different device from the one you have been using.
Example
Could not read on a PC
→ Try on a smartphone using a mobile data environment
→ Try on a colleague's PC
→ Try on a tablet at home
The problem is often solved by trying from another device (smartphone, tablet, or PC).
Please try once more.
Inquiring with Ondoku about the error
Contacting Ondoku helps in investigating the cause of the error.
Ondoku's management can check "error logs," which are histories showing the situation in which the error occurred.
Customers cannot view these error logs themselves.
If you want to investigate the cause of an error, please contact Ondoku customer support through Contact Us.
Ondoku customer support provides a reply within 24 hours on business days.
- For non-members
We cannot investigate the cause of the error. Please register as a member. - For members
We will provide email support to investigate the cause of the error.
When making an inquiry,
- The account experiencing the issue:
- The browser you are using:
- Approximate time of occurrence:
- Language:
- Voice type:
- Settings such as speed:
- I tried the Incognito window
- I tried from another device (smartphone, tablet, PC)
- Is the error still occurring now:
- The text that caused the error (the full text you tried to read):
please include the above information when contacting us.
Providing the above information will speed up the investigation and resolution of the cause of the error.
Investigating the cause of the error will allow you to use Ondoku even more comfortably.
At Ondoku, nothing makes us happier than being of service to you.
Please take this opportunity to contact Ondoku customer support.
We will provide our full support.
We hope to continue being the best text-to-speech software for you.
Thank you for your continued support of Ondoku.
■ AI voice synthesis software "Ondoku"
"Ondoku" is an online text-to-speech tool that can be used with no initial costs.
- Supports approximately 50 languages, including Japanese, English, Chinese, Korean, Spanish, French, and German
- Available from both PC and smartphone
- Suitable for business, education, entertainment, etc.
- No installation required, can be used immediately from your browser
- Supports reading from images
To use it, simply enter text or upload a file on the site. A natural-sounding audio file will be generated within seconds. You can use voice synthesis up to 5,000 characters for free, so please give it a try.
Email: ondoku3.com@gmail.com
"Ondoku" is a Text-to-Speech service that anyone can use for free without installation. If you register for free, you can get up to 5000 characters for free each month. Register now for free
- What is Ondoku
- Start text-to-speech conversion
- Free registration
- Pricing
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